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<div id="msg">
<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/192421">192421</a></dd>
<dt>Author</dt> <dd>matthew_hanson@apple.com</dd>
<dt>Date</dt> <dd>2015-11-13 09:03:00 -0800 (Fri, 13 Nov 2015)</dd>
</dl>

<h3>Log Message</h3>
<pre>Merge <a href="http://trac.webkit.org/projects/webkit/changeset/188514">r188514</a>. rdar://problem/23432371</pre>

<h3>Modified Paths</h3>
<ul>
<li><a href="#branchessafari601146branchLayoutTestsChangeLog">branches/safari-601.1.46-branch/LayoutTests/ChangeLog</a></li>
<li><a href="#branchessafari601146branchLayoutTestsplatformeflTestExpectations">branches/safari-601.1.46-branch/LayoutTests/platform/efl/TestExpectations</a></li>
<li><a href="#branchessafari601146branchLayoutTestsplatformmacmavericksTestExpectations">branches/safari-601.1.46-branch/LayoutTests/platform/mac-mavericks/TestExpectations</a></li>
<li><a href="#branchessafari601146branchSourceWebCoreChangeLog">branches/safari-601.1.46-branch/Source/WebCore/ChangeLog</a></li>
<li><a href="#branchessafari601146branchSourceWebCorecssStyleResolvercpp">branches/safari-601.1.46-branch/Source/WebCore/css/StyleResolver.cpp</a></li>
<li><a href="#branchessafari601146branchSourceWebCorerenderingstyleRenderStyleh">branches/safari-601.1.46-branch/Source/WebCore/rendering/style/RenderStyle.h</a></li>
<li><a href="#branchessafari601146branchSourceWebCorerenderingstyleWillChangeDatacpp">branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.cpp</a></li>
<li><a href="#branchessafari601146branchSourceWebCorerenderingstyleWillChangeDatah">branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.h</a></li>
</ul>

<h3>Added Paths</h3>
<ul>
<li>branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/</li>
<li>branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/resources/</li>
<li><a href="#branchessafari601146branchLayoutTestsfastcsswillchangeresourceswillchangestackinghelperjs">branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/resources/will-change-stacking-helper.js</a></li>
<li><a href="#branchessafari601146branchLayoutTestsfastcsswillchangewillchangecreatesstackingcontextexpectedhtml">branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context-expected.html</a></li>
<li><a href="#branchessafari601146branchLayoutTestsfastcsswillchangewillchangecreatesstackingcontexthtml">branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context.html</a></li>
</ul>

</div>
<div id="patch">
<h3>Diff</h3>
<a id="branchessafari601146branchLayoutTestsChangeLog"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/LayoutTests/ChangeLog (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/LayoutTests/ChangeLog        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/LayoutTests/ChangeLog        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -1,5 +1,25 @@
</span><span class="cx"> 2015-11-13  Matthew Hanson  &lt;matthew_hanson@apple.com&gt;
</span><span class="cx"> 
</span><ins>+        Merge r188514. rdar://problem/23432371
+
+    2015-08-15  Simon Fraser  &lt;simon.fraser@apple.com&gt;
+
+            Have will-change create stacking context when necessary
+            https://bugs.webkit.org/show_bug.cgi?id=148060
+
+            Reviewed by Zalan Bujtas.
+
+            Ref test for will-change creating stacking context.
+
+            * fast/css/will-change/resources/will-change-stacking-helper.js: Added.
+            (makeStackingBlock):
+            * fast/css/will-change/will-change-creates-stacking-context-expected.html: Added.
+            * fast/css/will-change/will-change-creates-stacking-context.html: Added.
+            * platform/efl/TestExpectations: Mark image failure on EFL, since some CSS
+            properties in the test are disabled there.
+
+2015-11-13  Matthew Hanson  &lt;matthew_hanson@apple.com&gt;
+
</ins><span class="cx">         Merge r188512. rdar://problem/23432371
</span><span class="cx"> 
</span><span class="cx">     2015-08-14  Simon Fraser  &lt;simon.fraser@apple.com&gt;
</span></span></pre></div>
<a id="branchessafari601146branchLayoutTestsfastcsswillchangeresourceswillchangestackinghelperjs"></a>
<div class="addfile"><h4>Added: branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/resources/will-change-stacking-helper.js (0 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/resources/will-change-stacking-helper.js                                (rev 0)
+++ branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/resources/will-change-stacking-helper.js        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -0,0 +1,51 @@
</span><ins>+var willChangeValues = [
+    { 'property' : 'auto', 'stacking' : false },
+    { 'property' : 'background', 'stacking' : false },
+    { 'property' : 'will-change', 'stacking' : false },
+
+    { 'property' : 'clip-path', 'stacking' : true },
+    { 'property' : 'mask', 'stacking' : true },
+    { 'property' : 'opacity', 'stacking' : true },
+    { 'property' : 'position', 'stacking' : true },
+    { 'property' : 'z-index', 'stacking' : true },
+    { 'property' : 'mix-blend-mode', 'stacking' : true },
+    { 'property' : 'isolation', 'stacking' : true },
+    { 'property' : 'perspective', 'stacking' : true },
+    { 'property' : 'transform', 'stacking' : true },
+    { 'property' : 'transform-style', 'stacking' : true },
+
+    { 'property' : '-webkit-filter', 'stacking' : true },
+    { 'property' : '-webkit-clip-path', 'stacking' : true },
+    { 'property' : '-webkit-backface-visibility', 'stacking' : true },
+    { 'property' : '-webkit-box-reflect', 'stacking' : true },
+    { 'property' : '-webkit-backdrop-filter', 'stacking' : true },
+    { 'property' : '-webkit-mask', 'stacking' : true },
+    { 'property' : '-webkit-mask-image', 'stacking' : true },
+    { 'property' : '-webkit-mask-box-image', 'stacking' : true },
+    { 'property' : '-webkit-transform', 'stacking' : true },
+    { 'property' : '-webkit-transform-style', 'stacking' : true },
+    { 'property' : '-webkit-flow-from', 'stacking' : true },
+];
+
+function makeStackingBlock(stackingProperty, value)
+{
+    var container = document.createElement('div');
+    container.className = 'container';
+
+    var potentialStackingContext = document.createElement('div');
+    potentialStackingContext.className = 'potential-stacking-context';
+    potentialStackingContext.style[stackingProperty] = value;
+
+    var child = document.createElement('div');
+    child.className = 'child';
+    potentialStackingContext.appendChild(child);
+
+    container.appendChild(potentialStackingContext);
+
+    var interposer = document.createElement('div');
+    interposer.className = 'interposer';
+    container.appendChild(interposer);
+    
+    document.body.appendChild(container);
+}
+
</ins></span></pre></div>
<a id="branchessafari601146branchLayoutTestsfastcsswillchangewillchangecreatesstackingcontextexpectedhtml"></a>
<div class="addfile"><h4>Added: branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context-expected.html (0 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context-expected.html                                (rev 0)
+++ branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context-expected.html        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -0,0 +1,57 @@
</span><ins>+&lt;!DOCTYPE html&gt;
+
+&lt;html&gt;
+&lt;head&gt;
+    &lt;style&gt;
+        .container {
+            display: inline-block;
+            margin: 25px;
+            width: 50px;
+            height: 50px;
+            position: relative;
+            border: 1px solid black;
+        }
+        
+        .container div {
+            width: 100%;
+            height: 100%;
+        }
+        
+        .potential-stacking-context {
+            position: relative;
+            z-index: auto;
+            background-color: silver;
+        }
+        
+        .child {
+            position: absolute;
+            top: 10px;
+            left: 10px;
+            z-index: 1;
+            background-color: orange;
+        }
+
+        .interposer {
+            position: absolute;
+            top: 20px;
+            left: 20px;
+            z-index: 0;
+            background-color: green;
+        }
+    &lt;/style&gt;
+
+    &lt;script src=&quot;resources/will-change-stacking-helper.js&quot;&gt;&lt;/script&gt;
+    &lt;script&gt;
+        function doTest()
+        {
+            for (value of willChangeValues) {
+                makeStackingBlock('z-index', value.stacking ? '0' : 'auto');
+            }
+        }
+        
+        window.addEventListener('load', doTest, false);
+    &lt;/script&gt;
+&lt;/head&gt;
+&lt;body&gt;
+&lt;/body&gt;
+&lt;/html&gt;
</ins></span></pre></div>
<a id="branchessafari601146branchLayoutTestsfastcsswillchangewillchangecreatesstackingcontexthtml"></a>
<div class="addfile"><h4>Added: branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context.html (0 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context.html                                (rev 0)
+++ branches/safari-601.1.46-branch/LayoutTests/fast/css/will-change/will-change-creates-stacking-context.html        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -0,0 +1,57 @@
</span><ins>+&lt;!DOCTYPE html&gt;
+
+&lt;html&gt;
+&lt;head&gt;
+    &lt;style&gt;
+        .container {
+            display: inline-block;
+            margin: 25px;
+            width: 50px;
+            height: 50px;
+            position: relative;
+            border: 1px solid black;
+        }
+        
+        .container div {
+            width: 100%;
+            height: 100%;
+        }
+        
+        .potential-stacking-context {
+            position: relative;
+            z-index: auto;
+            background-color: silver;
+        }
+        
+        .child {
+            position: absolute;
+            top: 10px;
+            left: 10px;
+            z-index: 1;
+            background-color: orange;
+        }
+
+        .interposer {
+            position: absolute;
+            top: 20px;
+            left: 20px;
+            z-index: 0;
+            background-color: green;
+        }
+    &lt;/style&gt;
+
+    &lt;script src=&quot;resources/will-change-stacking-helper.js&quot;&gt;&lt;/script&gt;
+    &lt;script&gt;
+        function doTest()
+        {
+            for (value of willChangeValues) {
+                makeStackingBlock('will-change', value.property);
+            }
+        }
+        
+        window.addEventListener('load', doTest, false);
+    &lt;/script&gt;
+&lt;/head&gt;
+&lt;body&gt;
+&lt;/body&gt;
+&lt;/html&gt;
</ins></span></pre></div>
<a id="branchessafari601146branchLayoutTestsplatformeflTestExpectations"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/LayoutTests/platform/efl/TestExpectations (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/LayoutTests/platform/efl/TestExpectations        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/LayoutTests/platform/efl/TestExpectations        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -314,6 +314,9 @@
</span><span class="cx"> # CSS image-resolution is not yet enabled.
</span><span class="cx"> webkit.org/b/85262 fast/css/image-resolution
</span><span class="cx"> 
</span><ins>+# Some CSS properties not supported on EFL
+fast/css/will-change/will-change-creates-stacking-context.html [ ImageOnlyFailure ]
+
</ins><span class="cx"> # Perf tests are really slow in debug builds and there are few benefits in running them.
</span><span class="cx"> [ Debug ] perf [ WontFix ]
</span><span class="cx"> 
</span></span></pre></div>
<a id="branchessafari601146branchLayoutTestsplatformmacmavericksTestExpectations"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/LayoutTests/platform/mac-mavericks/TestExpectations (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/LayoutTests/platform/mac-mavericks/TestExpectations        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/LayoutTests/platform/mac-mavericks/TestExpectations        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -9,6 +9,7 @@
</span><span class="cx"> # No support for Filters Level 2
</span><span class="cx"> compositing/media-controls-bar-appearance.html [ Skip ]
</span><span class="cx"> compositing/media-controls-bar-appearance-big.html [ Skip ]
</span><ins>+fast/css/will-change/will-change-creates-stacking-context.html [ ImageOnlyFailure ]
</ins><span class="cx"> 
</span><span class="cx"> # No support for non-HLS Media Selection Group
</span><span class="cx"> media/accessiblity-describes-video.html [ Skip ]
</span></span></pre></div>
<a id="branchessafari601146branchSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/Source/WebCore/ChangeLog (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/Source/WebCore/ChangeLog        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/Source/WebCore/ChangeLog        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -1,5 +1,31 @@
</span><span class="cx"> 2015-11-13  Matthew Hanson  &lt;matthew_hanson@apple.com&gt;
</span><span class="cx"> 
</span><ins>+        Merge r188514. rdar://problem/23432371
+
+    2015-08-15  Simon Fraser  &lt;simon.fraser@apple.com&gt;
+
+            Have will-change create stacking context when necessary
+            https://bugs.webkit.org/show_bug.cgi?id=148060
+
+            Reviewed by Zalan Bujtas.
+
+            If will-change includes a property whose non-initial value can create
+            stacking context, create stacking context for that element.
+
+            Test: fast/css/will-change/will-change-creates-stacking-context.html
+
+            * css/StyleResolver.cpp:
+            (WebCore::StyleResolver::adjustRenderStyle):
+            * rendering/style/RenderStyle.h: Add willChangeCreatesStackingContext(),
+            which on most cases is a fast, inlined 'return false'. Otherwise ask
+            the WillChangeData.
+            * rendering/style/WillChangeData.cpp:
+            (WebCore::propertyCreatesStackingContext):
+            (WebCore::WillChangeData::createsStackingContext):
+            * rendering/style/WillChangeData.h:
+
+2015-11-13  Matthew Hanson  &lt;matthew_hanson@apple.com&gt;
+
</ins><span class="cx">         Merge r188512. rdar://problem/23432371
</span><span class="cx"> 
</span><span class="cx">     2015-08-14  Simon Fraser  &lt;simon.fraser@apple.com&gt;
</span></span></pre></div>
<a id="branchessafari601146branchSourceWebCorecssStyleResolvercpp"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/Source/WebCore/css/StyleResolver.cpp (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/Source/WebCore/css/StyleResolver.cpp        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/Source/WebCore/css/StyleResolver.cpp        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -1269,6 +1269,7 @@
</span><span class="cx">         || style.position() == StickyPosition
</span><span class="cx">         || (style.position() == FixedPosition &amp;&amp; documentSettings() &amp;&amp; documentSettings()-&gt;fixedPositionCreatesStackingContext())
</span><span class="cx">         || style.hasFlowFrom()
</span><ins>+        || style.willChangeCreatesStackingContext()
</ins><span class="cx">         ))
</span><span class="cx">         style.setZIndex(0);
</span><span class="cx"> 
</span></span></pre></div>
<a id="branchessafari601146branchSourceWebCorerenderingstyleRenderStyleh"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/Source/WebCore/rendering/style/RenderStyle.h (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/Source/WebCore/rendering/style/RenderStyle.h        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/Source/WebCore/rendering/style/RenderStyle.h        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -113,7 +113,6 @@
</span><span class="cx"> class StyleInheritedData;
</span><span class="cx"> class StyleResolver;
</span><span class="cx"> class TransformationMatrix;
</span><del>-class WillChangeData;
</del><span class="cx"> 
</span><span class="cx"> struct ScrollSnapPoints;
</span><span class="cx"> 
</span><span class="lines">@@ -1801,6 +1800,14 @@
</span><span class="cx">     WillChangeData* willChange() const { return rareNonInheritedData-&gt;m_willChange.get(); }
</span><span class="cx">     void setWillChange(PassRefPtr&lt;WillChangeData&gt;);
</span><span class="cx"> 
</span><ins>+    bool willChangeCreatesStackingContext() const
+    {
+        if (!willChange())
+            return false;
+        
+        return willChange()-&gt;createsStackingContext();
+    }
+
</ins><span class="cx">     const AtomicString&amp; hyphenString() const;
</span><span class="cx"> 
</span><span class="cx">     bool inheritedNotEqual(const RenderStyle*) const;
</span></span></pre></div>
<a id="branchessafari601146branchSourceWebCorerenderingstyleWillChangeDatacpp"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.cpp (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.cpp        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.cpp        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -60,6 +60,55 @@
</span><span class="cx">     return false;
</span><span class="cx"> }
</span><span class="cx"> 
</span><ins>+// &quot;If any non-initial value of a property would create a stacking context on the element,
+// specifying that property in will-change must create a stacking context on the element.&quot;
+static bool propertyCreatesStackingContext(CSSPropertyID property)
+{
+    switch (property) {
+    case CSSPropertyClipPath:
+    case CSSPropertyWebkitClipPath:
+    case CSSPropertyMask:
+    case CSSPropertyOpacity:
+    case CSSPropertyPosition:
+    case CSSPropertyZIndex:
+    case CSSPropertyWebkitBackfaceVisibility:
+    case CSSPropertyWebkitBoxReflect:
+#if ENABLE(CSS_COMPOSITING)
+    case CSSPropertyMixBlendMode:
+    case CSSPropertyIsolation:
+#endif
+    case CSSPropertyWebkitFilter:
+#if ENABLE(FILTERS_LEVEL_2)
+    case CSSPropertyWebkitBackdropFilter:
+#endif
+    case CSSPropertyWebkitMask:
+    case CSSPropertyWebkitMaskImage:
+    case CSSPropertyWebkitMaskBoxImage:
+    case CSSPropertyPerspective:
+    case CSSPropertyTransform:
+    case CSSPropertyTransformStyle:
+    case CSSPropertyWebkitTransformStyle:
+#if ENABLE(CSS_REGIONS)
+    case CSSPropertyWebkitFlowFrom:
+#endif
+#if ENABLE(ACCELERATED_OVERFLOW_SCROLLING)
+    case CSSPropertyWebkitOverflowScrolling:
+#endif
+        return true;
+    default:
+        return false;
+    }
+}
+
+bool WillChangeData::createsStackingContext() const
+{
+    for (const auto&amp; feature : m_animatableFeatures) {
+        if (feature.feature() == Property &amp;&amp; propertyCreatesStackingContext(feature.property()))
+            return true;
+    }
+    return false;
+}
+
</ins><span class="cx"> void WillChangeData::addFeature(Feature feature, CSSPropertyID propertyID)
</span><span class="cx"> {
</span><span class="cx">     ASSERT(feature == Property || propertyID == CSSPropertyInvalid);
</span></span></pre></div>
<a id="branchessafari601146branchSourceWebCorerenderingstyleWillChangeDatah"></a>
<div class="modfile"><h4>Modified: branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.h (192420 => 192421)</h4>
<pre class="diff"><span>
<span class="info">--- branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.h        2015-11-13 17:02:56 UTC (rev 192420)
+++ branches/safari-601.1.46-branch/Source/WebCore/rendering/style/WillChangeData.h        2015-11-13 17:03:00 UTC (rev 192421)
</span><span class="lines">@@ -53,6 +53,7 @@
</span><span class="cx">     bool containsScrollPosition() const;
</span><span class="cx">     bool containsContents() const;
</span><span class="cx">     bool containsProperty(CSSPropertyID) const;
</span><ins>+    bool createsStackingContext() const;
</ins><span class="cx"> 
</span><span class="cx">     enum Feature {
</span><span class="cx">         ScrollPosition,
</span></span></pre>
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