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<div id="msg">
<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/243318">243318</a></dd>
<dt>Author</dt> <dd>simon.fraser@apple.com</dd>
<dt>Date</dt> <dd>2019-03-21 13:20:14 -0700 (Thu, 21 Mar 2019)</dd>
</dl>

<h3>Log Message</h3>
<pre>Add an internal feature flag to disable the -webkit-overflow-scrolling CSS property
https://bugs.webkit.org/show_bug.cgi?id=196058
rdar://problem/49078202

Reviewed by Antti Koivisto.
Source/WebCore:

Add an internal setting called "legacyOverflowScrollingTouchEnabled", initially
on by default.

When disabled, it makes the -webkit-overflow-scrolling property be unsupported.

Tests: fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html
       fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html

* css/parser/CSSParserContext.cpp:
(WebCore::CSSParserContext::CSSParserContext):
(WebCore::operator==):
* css/parser/CSSParserContext.h:
(WebCore::CSSParserContextHash::hash):
* css/parser/CSSParserFastPaths.cpp:
(WebCore::CSSParserFastPaths::isValidKeywordPropertyAndValue):
* css/parser/CSSParserFastPaths.h:
* css/parser/CSSPropertyParser.cpp:
(WebCore::CSSPropertyParser::parseSingleValue):
* page/Settings.yaml:

Source/WebKit:

Add an internal feature flag called "LegacyOverflowScrollingTouchEnabled", initially
on by default.

* Shared/WebPreferences.yaml:

LayoutTests:

Add tests testing that the stacking-context side-effects -webkit-overflow-scrolling:touch
go away when it's disabled.

* fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking-expected.html: Added.
* fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html: Added.
* fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking-expected.html: Added.
* fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html: Added.</pre>

<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkLayoutTestsChangeLog">trunk/LayoutTests/ChangeLog</a></li>
<li><a href="#trunkSourceWebCoreChangeLog">trunk/Source/WebCore/ChangeLog</a></li>
<li><a href="#trunkSourceWebCorecssparserCSSParserContextcpp">trunk/Source/WebCore/css/parser/CSSParserContext.cpp</a></li>
<li><a href="#trunkSourceWebCorecssparserCSSParserContexth">trunk/Source/WebCore/css/parser/CSSParserContext.h</a></li>
<li><a href="#trunkSourceWebCorecssparserCSSParserFastPathscpp">trunk/Source/WebCore/css/parser/CSSParserFastPaths.cpp</a></li>
<li><a href="#trunkSourceWebCorecssparserCSSParserFastPathsh">trunk/Source/WebCore/css/parser/CSSParserFastPaths.h</a></li>
<li><a href="#trunkSourceWebCorecssparserCSSPropertyParsercpp">trunk/Source/WebCore/css/parser/CSSPropertyParser.cpp</a></li>
<li><a href="#trunkSourceWebCoreinspectoragentsInspectorCSSAgentcpp">trunk/Source/WebCore/inspector/agents/InspectorCSSAgent.cpp</a></li>
<li><a href="#trunkSourceWebCorepageSettingsyaml">trunk/Source/WebCore/page/Settings.yaml</a></li>
<li><a href="#trunkSourceWebKitChangeLog">trunk/Source/WebKit/ChangeLog</a></li>
<li><a href="#trunkSourceWebKitSharedWebPreferencesyaml">trunk/Source/WebKit/Shared/WebPreferences.yaml</a></li>
</ul>

<h3>Added Paths</h3>
<ul>
<li><a href="#trunkLayoutTestsfastscrollingiosoverflowscrollingtouchdisabledstackingexpectedhtml">trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking-expected.html</a></li>
<li><a href="#trunkLayoutTestsfastscrollingiosoverflowscrollingtouchdisabledstackinghtml">trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html</a></li>
<li><a href="#trunkLayoutTestsfastscrollingiosoverflowscrollingtouchenabledstackingexpectedhtml">trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking-expected.html</a></li>
<li><a href="#trunkLayoutTestsfastscrollingiosoverflowscrollingtouchenabledstackinghtml">trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html</a></li>
</ul>

</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkLayoutTestsChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/LayoutTests/ChangeLog (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/LayoutTests/ChangeLog      2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/LayoutTests/ChangeLog 2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -1,3 +1,19 @@
</span><ins>+2019-03-21  Simon Fraser  <simon.fraser@apple.com>
+
+        Add an internal feature flag to disable the -webkit-overflow-scrolling CSS property
+        https://bugs.webkit.org/show_bug.cgi?id=196058
+        rdar://problem/49078202
+
+        Reviewed by Antti Koivisto.
+        
+        Add tests testing that the stacking-context side-effects -webkit-overflow-scrolling:touch
+        go away when it's disabled.
+
+        * fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking-expected.html: Added.
+        * fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html: Added.
+        * fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking-expected.html: Added.
+        * fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html: Added.
+
</ins><span class="cx"> 2019-03-21  Devin Rousso  <drousso@apple.com>
</span><span class="cx"> 
</span><span class="cx">         Unreviewed, fix test failures after r243269.
</span></span></pre></div>
<a id="trunkLayoutTestsfastscrollingiosoverflowscrollingtouchdisabledstackingexpectedhtml"></a>
<div class="addfile"><h4>Added: trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking-expected.html (0 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking-expected.html                            (rev 0)
+++ trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking-expected.html       2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -0,0 +1,54 @@
</span><ins>+<!DOCTYPE html>
+<html>
+<head>
+    <style>
+        .box {
+            position: absolute;
+            height: 200px;
+            width: 200px;
+            background-color: blue;
+        }
+        
+        .scroller {
+            margin: 60px;
+            overflow: scroll;
+            border: 1px solid black;
+            width: 220px;
+            height: 220px;
+        }
+        
+        .scrolled-contents {
+            height: 1000px;
+        }
+        
+        .outside {
+            z-index: 1;
+            top: 20px;
+            left: 20px;
+            background-color: green;
+        }
+        
+        .back {
+            z-index: 0;
+        }
+        
+        .front {
+            z-index: 2;
+            top: 120px;
+            left: 120px;
+            width: 160px;
+            height: 160px;
+            background-color: orange;
+        }
+    </style>
+</head>
+<body>
+    <div class="outside box"></div>
+    <div class="scroller">
+        <div class="scrolled-contents">
+            <div class="back box"></div>
+            <div class="front box"></div>
+        </div>
+    </div>
+</body>
+</html>
</ins></span></pre></div>
<a id="trunkLayoutTestsfastscrollingiosoverflowscrollingtouchdisabledstackinghtml"></a>
<div class="addfile"><h4>Added: trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html (0 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html                             (rev 0)
+++ trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html        2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -0,0 +1,59 @@
</span><ins>+<!DOCTYPE html>
+<html>
+<head>
+    <script>
+        if (window.internals)
+            internals.settings.setLegacyOverflowScrollingTouchEnabled(false);
+    </script>
+    <style>
+        .box {
+            position: absolute;
+            height: 200px;
+            width: 200px;
+            background-color: blue;
+        }
+        
+        .scroller {
+            margin: 60px;
+            overflow: scroll;
+            border: 1px solid black;
+            width: 220px;
+            height: 220px;
+            -webkit-overflow-scrolling: touch;
+        }
+        
+        .scrolled-contents {
+            height: 1000px;
+        }
+        
+        .outside {
+            z-index: 1;
+            top: 20px;
+            left: 20px;
+            background-color: green;
+        }
+        
+        .back {
+            z-index: 0;
+        }
+        
+        .front {
+            z-index: 2;
+            top: 120px;
+            left: 120px;
+            width: 160px;
+            height: 160px;
+            background-color: orange;
+        }
+    </style>
+</head>
+<body>
+    <div class="outside box"></div>
+    <div class="scroller">
+        <div class="scrolled-contents">
+            <div class="back box"></div>
+            <div class="front box"></div>
+        </div>
+    </div>
+</body>
+</html>
</ins></span></pre></div>
<a id="trunkLayoutTestsfastscrollingiosoverflowscrollingtouchenabledstackingexpectedhtml"></a>
<div class="addfile"><h4>Added: trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking-expected.html (0 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking-expected.html                             (rev 0)
+++ trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking-expected.html        2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -0,0 +1,54 @@
</span><ins>+<!DOCTYPE html>
+<html>
+<head>
+    <style>
+        .box {
+            position: absolute;
+            height: 200px;
+            width: 200px;
+            background-color: blue;
+        }
+        
+        .scroller {
+            margin: 60px;
+            overflow: scroll;
+            border: 1px solid black;
+            width: 220px;
+            height: 220px;
+            -webkit-overflow-scrolling: touch;
+            will-change: z-index;
+        }
+        
+        .scrolled-contents {
+            height: 1000px;
+        }
+        
+        .outside {
+            z-index: 1;
+            top: 20px;
+            left: 20px;
+            background-color: green;
+        }
+        
+        .back {
+            z-index: 0;
+        }
+        
+        .front {
+            z-index: 2;
+            top: 120px;
+            left: 120px;
+            background-color: orange;
+        }
+    </style>
+</head>
+<body>
+    <div class="outside box"></div>
+    <div class="scroller">
+        <div class="scrolled-contents">
+            <div class="back box"></div>
+            <div class="front box"></div>
+        </div>
+    </div>
+</body>
+</html>
</ins></span></pre></div>
<a id="trunkLayoutTestsfastscrollingiosoverflowscrollingtouchenabledstackinghtml"></a>
<div class="addfile"><h4>Added: trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html (0 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html                              (rev 0)
+++ trunk/LayoutTests/fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html 2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -0,0 +1,57 @@
</span><ins>+<!DOCTYPE html>
+<html>
+<head>
+    <script>
+        if (window.internals)
+            internals.settings.setLegacyOverflowScrollingTouchEnabled(true);
+    </script>
+    <style>
+        .box {
+            position: absolute;
+            height: 200px;
+            width: 200px;
+            background-color: blue;
+        }
+        
+        .scroller {
+            margin: 60px;
+            overflow: scroll;
+            border: 1px solid black;
+            width: 220px;
+            height: 220px;
+            -webkit-overflow-scrolling: touch;
+        }
+        
+        .scrolled-contents {
+            height: 1000px;
+        }
+        
+        .outside {
+            z-index: 1;
+            top: 20px;
+            left: 20px;
+            background-color: green;
+        }
+        
+        .back {
+            z-index: 0;
+        }
+        
+        .front {
+            z-index: 2;
+            top: 120px;
+            left: 120px;
+            background-color: orange;
+        }
+    </style>
+</head>
+<body>
+    <div class="outside box"></div>
+    <div class="scroller">
+        <div class="scrolled-contents">
+            <div class="back box"></div>
+            <div class="front box"></div>
+        </div>
+    </div>
+</body>
+</html>
</ins></span></pre></div>
<a id="trunkSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/ChangeLog (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/ChangeLog   2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/ChangeLog      2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -1,3 +1,31 @@
</span><ins>+2019-03-21  Simon Fraser  <simon.fraser@apple.com>
+
+        Add an internal feature flag to disable the -webkit-overflow-scrolling CSS property
+        https://bugs.webkit.org/show_bug.cgi?id=196058
+        rdar://problem/49078202
+
+        Reviewed by Antti Koivisto.
+
+        Add an internal setting called "legacyOverflowScrollingTouchEnabled", initially
+        on by default.
+
+        When disabled, it makes the -webkit-overflow-scrolling property be unsupported.
+
+        Tests: fast/scrolling/ios/overflow-scrolling-touch-disabled-stacking.html
+               fast/scrolling/ios/overflow-scrolling-touch-enabled-stacking.html
+
+        * css/parser/CSSParserContext.cpp:
+        (WebCore::CSSParserContext::CSSParserContext):
+        (WebCore::operator==):
+        * css/parser/CSSParserContext.h:
+        (WebCore::CSSParserContextHash::hash):
+        * css/parser/CSSParserFastPaths.cpp:
+        (WebCore::CSSParserFastPaths::isValidKeywordPropertyAndValue):
+        * css/parser/CSSParserFastPaths.h:
+        * css/parser/CSSPropertyParser.cpp:
+        (WebCore::CSSPropertyParser::parseSingleValue):
+        * page/Settings.yaml:
+
</ins><span class="cx"> 2019-03-21  Antti Koivisto  <antti@apple.com>
</span><span class="cx"> 
</span><span class="cx">         UI-process hit-testing needs to know about containing block relationships
</span></span></pre></div>
<a id="trunkSourceWebCorecssparserCSSParserContextcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/parser/CSSParserContext.cpp (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/parser/CSSParserContext.cpp     2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/css/parser/CSSParserContext.cpp        2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -58,6 +58,9 @@
</span><span class="cx"> #if ENABLE(TEXT_AUTOSIZING)
</span><span class="cx">     textAutosizingEnabled = document.settings().textAutosizingEnabled();
</span><span class="cx"> #endif
</span><ins>+#if ENABLE(OVERFLOW_SCROLLING_TOUCH)
+    legacyOverflowScrollingTouchEnabled = document.settings().legacyOverflowScrollingTouchEnabled();
+#endif
</ins><span class="cx">     springTimingFunctionEnabled = document.settings().springTimingFunctionEnabled();
</span><span class="cx">     constantPropertiesEnabled = document.settings().constantPropertiesEnabled();
</span><span class="cx">     colorFilterEnabled = document.settings().colorFilterEnabled();
</span><span class="lines">@@ -77,6 +80,9 @@
</span><span class="cx"> #if ENABLE(TEXT_AUTOSIZING)
</span><span class="cx">         && a.textAutosizingEnabled == b.textAutosizingEnabled
</span><span class="cx"> #endif
</span><ins>+#if ENABLE(OVERFLOW_SCROLLING_TOUCH)
+        && a.legacyOverflowScrollingTouchEnabled == b.legacyOverflowScrollingTouchEnabled
+#endif
</ins><span class="cx">         && a.enforcesCSSMIMETypeInNoQuirksMode == b.enforcesCSSMIMETypeInNoQuirksMode
</span><span class="cx">         && a.useLegacyBackgroundSizeShorthandBehavior == b.useLegacyBackgroundSizeShorthandBehavior
</span><span class="cx">         && a.springTimingFunctionEnabled == b.springTimingFunctionEnabled
</span></span></pre></div>
<a id="trunkSourceWebCorecssparserCSSParserContexth"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/parser/CSSParserContext.h (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/parser/CSSParserContext.h       2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/css/parser/CSSParserContext.h  2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -49,6 +49,9 @@
</span><span class="cx"> #if ENABLE(TEXT_AUTOSIZING)
</span><span class="cx">     bool textAutosizingEnabled { false };
</span><span class="cx"> #endif
</span><ins>+#if ENABLE(OVERFLOW_SCROLLING_TOUCH)
+    bool legacyOverflowScrollingTouchEnabled { false };
+#endif
</ins><span class="cx">     bool enforcesCSSMIMETypeInNoQuirksMode { true };
</span><span class="cx">     bool useLegacyBackgroundSizeShorthandBehavior { false };
</span><span class="cx">     bool springTimingFunctionEnabled { false };
</span><span class="lines">@@ -93,18 +96,21 @@
</span><span class="cx"> #if ENABLE(TEXT_AUTOSIZING)
</span><span class="cx">             & key.textAutosizingEnabled                     << 1
</span><span class="cx"> #endif
</span><del>-            & key.enforcesCSSMIMETypeInNoQuirksMode         << 2
-            & key.useLegacyBackgroundSizeShorthandBehavior  << 3
-            & key.springTimingFunctionEnabled               << 4
-            & key.constantPropertiesEnabled                 << 5
-            & key.colorFilterEnabled                        << 6
-            & key.deferredCSSParserEnabled                  << 7
-            & key.hasDocumentSecurityOrigin                 << 8
-            & key.useSystemAppearance                       << 9
</del><ins>+#if ENABLE(OVERFLOW_SCROLLING_TOUCH)
+            & key.legacyOverflowScrollingTouchEnabled       << 2
+#endif
+            & key.enforcesCSSMIMETypeInNoQuirksMode         << 3
+            & key.useLegacyBackgroundSizeShorthandBehavior  << 4
+            & key.springTimingFunctionEnabled               << 5
+            & key.constantPropertiesEnabled                 << 6
+            & key.colorFilterEnabled                        << 7
+            & key.deferredCSSParserEnabled                  << 8
+            & key.hasDocumentSecurityOrigin                 << 9
+            & key.useSystemAppearance                       << 10
</ins><span class="cx"> #if ENABLE(ATTACHMENT_ELEMENT)
</span><del>-            & key.attachmentEnabled                         << 10
</del><ins>+            & key.attachmentEnabled                         << 11
</ins><span class="cx"> #endif
</span><del>-            & key.mode                                      << 11; // Keep this last.
</del><ins>+            & key.mode                                      << 12; // Keep this last.
</ins><span class="cx">         hash ^= WTF::intHash(bits);
</span><span class="cx">         return hash;
</span><span class="cx">     }
</span></span></pre></div>
<a id="trunkSourceWebCorecssparserCSSParserFastPathscpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/parser/CSSParserFastPaths.cpp (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/parser/CSSParserFastPaths.cpp   2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/css/parser/CSSParserFastPaths.cpp      2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -31,6 +31,7 @@
</span><span class="cx"> #include "CSSParserFastPaths.h"
</span><span class="cx"> 
</span><span class="cx"> #include "CSSFunctionValue.h"
</span><ins>+#include "CSSParserContext.h"
</ins><span class="cx"> #include "CSSParserIdioms.h"
</span><span class="cx"> #include "CSSPrimitiveValue.h"
</span><span class="cx"> #include "CSSPropertyParser.h"
</span><span class="lines">@@ -519,9 +520,13 @@
</span><span class="cx">     return CSSValuePool::singleton().createColorValue(color);
</span><span class="cx"> }
</span><span class="cx"> 
</span><del>-bool CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyID propertyId, CSSValueID valueID, CSSParserMode parserMode)
</del><ins>+bool CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyID propertyId, CSSValueID valueID, const CSSParserContext& context)
</ins><span class="cx"> {
</span><del>-    if (valueID == CSSValueInvalid || !isValueAllowedInMode(valueID, parserMode))
</del><ins>+#if !ENABLE(OVERFLOW_SCROLLING_TOUCH)
+    UNUSED_PARAM(context);
+#endif
+
+    if (valueID == CSSValueInvalid || !isValueAllowedInMode(valueID, context.mode))
</ins><span class="cx">         return false;
</span><span class="cx"> 
</span><span class="cx">     switch (propertyId) {
</span><span class="lines">@@ -802,6 +807,8 @@
</span><span class="cx">         return valueID == CSSValueNormal || valueID == CSSValueHistoricalForms;
</span><span class="cx"> #if ENABLE(OVERFLOW_SCROLLING_TOUCH)
</span><span class="cx">     case CSSPropertyWebkitOverflowScrolling:
</span><ins>+        if (!context.legacyOverflowScrollingTouchEnabled)
+            return nullptr;
</ins><span class="cx">         return valueID == CSSValueAuto || valueID == CSSValueTouch;
</span><span class="cx"> #endif
</span><span class="cx"> #if ENABLE(VARIATION_FONTS)
</span><span class="lines">@@ -981,7 +988,7 @@
</span><span class="cx">     || equalLettersIgnoringASCIICase(string, "revert");
</span><span class="cx"> }
</span><span class="cx"> 
</span><del>-static RefPtr<CSSValue> parseKeywordValue(CSSPropertyID propertyId, const String& string, CSSParserMode parserMode)
</del><ins>+static RefPtr<CSSValue> parseKeywordValue(CSSPropertyID propertyId, const String& string, const CSSParserContext& context)
</ins><span class="cx"> {
</span><span class="cx">     ASSERT(!string.isEmpty());
</span><span class="cx"> 
</span><span class="lines">@@ -1013,7 +1020,7 @@
</span><span class="cx">     if (valueID == CSSValueRevert)
</span><span class="cx">         return CSSValuePool::singleton().createRevertValue();
</span><span class="cx">     
</span><del>-    if (CSSParserFastPaths::isValidKeywordPropertyAndValue(propertyId, valueID, parserMode))
</del><ins>+    if (CSSParserFastPaths::isValidKeywordPropertyAndValue(propertyId, valueID, context))
</ins><span class="cx">         return CSSPrimitiveValue::createIdentifier(valueID);
</span><span class="cx">     return nullptr;
</span><span class="cx"> }
</span><span class="lines">@@ -1292,15 +1299,15 @@
</span><span class="cx">     return CSSParserFastPaths::parseColor(string, parserMode);
</span><span class="cx"> }
</span><span class="cx"> 
</span><del>-RefPtr<CSSValue> CSSParserFastPaths::maybeParseValue(CSSPropertyID propertyID, const String& string, CSSParserMode parserMode)
</del><ins>+RefPtr<CSSValue> CSSParserFastPaths::maybeParseValue(CSSPropertyID propertyID, const String& string, const CSSParserContext& context)
</ins><span class="cx"> {
</span><del>-    if (auto result = parseSimpleLengthValue(propertyID, string, parserMode))
</del><ins>+    if (auto result = parseSimpleLengthValue(propertyID, string, context.mode))
</ins><span class="cx">         return result;
</span><span class="cx">     if (propertyID == CSSPropertyCaretColor)
</span><del>-        return parseCaretColor(string, parserMode);
</del><ins>+        return parseCaretColor(string, context.mode);
</ins><span class="cx">     if (isColorPropertyID(propertyID))
</span><del>-        return parseColor(string, parserMode);
-    if (auto result = parseKeywordValue(propertyID, string, parserMode))
</del><ins>+        return parseColor(string, context.mode);
+    if (auto result = parseKeywordValue(propertyID, string, context))
</ins><span class="cx">         return result;
</span><span class="cx">     return parseSimpleTransform(propertyID, string);
</span><span class="cx"> }
</span></span></pre></div>
<a id="trunkSourceWebCorecssparserCSSParserFastPathsh"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/parser/CSSParserFastPaths.h (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/parser/CSSParserFastPaths.h     2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/css/parser/CSSParserFastPaths.h        2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -38,16 +38,17 @@
</span><span class="cx"> 
</span><span class="cx"> class CSSValue;
</span><span class="cx"> class StyleSheetContents;
</span><ins>+struct CSSParserContext;
</ins><span class="cx"> 
</span><span class="cx"> class CSSParserFastPaths {
</span><span class="cx"> public:
</span><span class="cx">     // Parses simple values like '10px' or 'green', but makes no guarantees
</span><span class="cx">     // about handling any property completely.
</span><del>-    static RefPtr<CSSValue> maybeParseValue(CSSPropertyID, const String&, CSSParserMode);
</del><ins>+    static RefPtr<CSSValue> maybeParseValue(CSSPropertyID, const String&, const CSSParserContext&);
</ins><span class="cx"> 
</span><span class="cx">     // Properties handled here shouldn't be explicitly handled in CSSPropertyParser
</span><span class="cx">     static bool isKeywordPropertyID(CSSPropertyID);
</span><del>-    static bool isValidKeywordPropertyAndValue(CSSPropertyID, CSSValueID, CSSParserMode);
</del><ins>+    static bool isValidKeywordPropertyAndValue(CSSPropertyID, CSSValueID, const CSSParserContext&);
</ins><span class="cx"> 
</span><span class="cx">     static RefPtr<CSSValue> parseColor(const String&, CSSParserMode);
</span><span class="cx"> };
</span></span></pre></div>
<a id="trunkSourceWebCorecssparserCSSPropertyParsercpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/parser/CSSPropertyParser.cpp (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/parser/CSSPropertyParser.cpp    2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/css/parser/CSSPropertyParser.cpp       2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -3909,8 +3909,9 @@
</span><span class="cx"> RefPtr<CSSValue> CSSPropertyParser::parseSingleValue(CSSPropertyID property, CSSPropertyID currentShorthand)
</span><span class="cx"> {
</span><span class="cx">     if (CSSParserFastPaths::isKeywordPropertyID(property)) {
</span><del>-        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(property, m_range.peek().id(), m_context.mode))
</del><ins>+        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(property, m_range.peek().id(), m_context))
</ins><span class="cx">             return nullptr;
</span><ins>+
</ins><span class="cx">         return consumeIdent(m_range);
</span><span class="cx">     }
</span><span class="cx">     switch (property) {
</span><span class="lines">@@ -5698,7 +5699,7 @@
</span><span class="cx">     switch (property) {
</span><span class="cx">     case CSSPropertyWebkitMarginCollapse: {
</span><span class="cx">         CSSValueID id = m_range.consumeIncludingWhitespace().id();
</span><del>-        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyWebkitMarginBeforeCollapse, id, m_context.mode))
</del><ins>+        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyWebkitMarginBeforeCollapse, id, m_context))
</ins><span class="cx">             return false;
</span><span class="cx">         addProperty(CSSPropertyWebkitMarginBeforeCollapse, CSSPropertyWebkitMarginCollapse, CSSValuePool::singleton().createIdentifierValue(id), important);
</span><span class="cx">         if (m_range.atEnd()) {
</span><span class="lines">@@ -5706,7 +5707,7 @@
</span><span class="cx">             return true;
</span><span class="cx">         }
</span><span class="cx">         id = m_range.consumeIncludingWhitespace().id();
</span><del>-        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyWebkitMarginAfterCollapse, id, m_context.mode))
</del><ins>+        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyWebkitMarginAfterCollapse, id, m_context))
</ins><span class="cx">             return false;
</span><span class="cx">         addProperty(CSSPropertyWebkitMarginAfterCollapse, CSSPropertyWebkitMarginCollapse, CSSValuePool::singleton().createIdentifierValue(id), important);
</span><span class="cx">         return true;
</span><span class="lines">@@ -5713,7 +5714,7 @@
</span><span class="cx">     }
</span><span class="cx">     case CSSPropertyOverflow: {
</span><span class="cx">         CSSValueID id = m_range.consumeIncludingWhitespace().id();
</span><del>-        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyOverflowY, id, m_context.mode))
</del><ins>+        if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(CSSPropertyOverflowY, id, m_context))
</ins><span class="cx">             return false;
</span><span class="cx">         if (!m_range.atEnd())
</span><span class="cx">             return false;
</span></span></pre></div>
<a id="trunkSourceWebCoreinspectoragentsInspectorCSSAgentcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/inspector/agents/InspectorCSSAgent.cpp (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/inspector/agents/InspectorCSSAgent.cpp      2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/inspector/agents/InspectorCSSAgent.cpp 2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -811,7 +811,7 @@
</span><span class="cx">             auto values = JSON::ArrayOf<String>::create();
</span><span class="cx">             for (int j = firstCSSValueKeyword; j <= lastCSSValueKeyword; ++j) {
</span><span class="cx">                 CSSValueID valueID = convertToCSSValueID(j);
</span><del>-                if (CSSParserFastPaths::isValidKeywordPropertyAndValue(propertyID, valueID, HTMLStandardMode))
</del><ins>+                if (CSSParserFastPaths::isValidKeywordPropertyAndValue(propertyID, valueID, strictCSSParserContext()))
</ins><span class="cx">                     values->addItem(getValueNameString(valueID));
</span><span class="cx">             }
</span><span class="cx">             if (values->length())
</span></span></pre></div>
<a id="trunkSourceWebCorepageSettingsyaml"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/page/Settings.yaml (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/page/Settings.yaml  2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebCore/page/Settings.yaml     2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -388,6 +388,11 @@
</span><span class="cx">   initial: false
</span><span class="cx">   onChange: setNeedsRelayoutAllFrames
</span><span class="cx"> 
</span><ins>+legacyOverflowScrollingTouchEnabled:
+  initial: true
+  onChange: setNeedsRelayoutAllFrames
+  conditional: OVERFLOW_SCROLLING_TOUCH
+
</ins><span class="cx"> webSecurityEnabled:
</span><span class="cx">   initial: true
</span><span class="cx">   inspectorOverride: true
</span></span></pre></div>
<a id="trunkSourceWebKitChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit/ChangeLog (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit/ChangeLog    2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebKit/ChangeLog       2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -1,3 +1,16 @@
</span><ins>+2019-03-21  Simon Fraser  <simon.fraser@apple.com>
+
+        Add an internal feature flag to disable the -webkit-overflow-scrolling CSS property
+        https://bugs.webkit.org/show_bug.cgi?id=196058
+        rdar://problem/49078202
+
+        Reviewed by Antti Koivisto.
+
+        Add an internal feature flag called "LegacyOverflowScrollingTouchEnabled", initially
+        on by default.
+
+        * Shared/WebPreferences.yaml:
+
</ins><span class="cx"> 2019-03-21  Antti Koivisto  <antti@apple.com>
</span><span class="cx"> 
</span><span class="cx">         UI-process hit-testing needs to know about containing block relationships
</span></span></pre></div>
<a id="trunkSourceWebKitSharedWebPreferencesyaml"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebKit/Shared/WebPreferences.yaml (243317 => 243318)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebKit/Shared/WebPreferences.yaml   2019-03-21 19:55:44 UTC (rev 243317)
+++ trunk/Source/WebKit/Shared/WebPreferences.yaml      2019-03-21 20:20:14 UTC (rev 243318)
</span><span class="lines">@@ -1442,6 +1442,14 @@
</span><span class="cx">   humanReadableDescription: "Perform overflow scrolling off the main thread"
</span><span class="cx">   category: internal
</span><span class="cx"> 
</span><ins>+LegacyOverflowScrollingTouchEnabled:
+  type: bool
+  defaultValue: true
+  humanReadableName: "Legacy -webkit-overflow-scrolling property"
+  humanReadableDescription: "Support the legacy -webkit-overflow-scrolling CSS property"
+  condition: ENABLE(OVERFLOW_SCROLLING_TOUCH)
+  category: internal
+
</ins><span class="cx"> FetchAPIKeepAliveEnabled:
</span><span class="cx">   type: bool
</span><span class="cx">   defaultValue: false
</span></span></pre>
</div>
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