[webkit-changes] [WebKit/WebKit] 42948c: Reduce calls to LayoutUnit and use default constru...

[Ahmad Saleem]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 42948cd0674a44230185146a56461d957488da8a
      https://github.com/WebKit/WebKit/commit/42948cd0674a44230185146a56461d957488da8a
  Author: Ahmad Saleem <ahmad.saleem792+github at gmail.com>
  Date:   2023-01-21 (Sat, 21 Jan 2023)

  Changed paths:
    M Source/WebCore/platform/graphics/LayoutPoint.h
    M Source/WebCore/platform/graphics/LayoutSize.h

  Log Message:
  -----------
  Reduce calls to LayoutUnit and use default constructors for containers

Reduce calls to LayoutUnit and use default constructors for containers
https://bugs.webkit.org/show_bug.cgi?id=250884

Reviewed by Alan Baradlay.

Merge (except RenderBox.h) - https://src.chromium.org/viewvc/blink?view=revision&revision=158483 &
https://src.chromium.org/viewvc/blink?view=rev&revision=158571

LayoutUnit() is fast; LayoutUnit(int) is slow because of bounds-checks.
Since the default constructor sets the m_value of the LayoutUnit to 0,
we can replace calls to LayoutUnit(0) with the default constructor.

The integer constructor of LayoutUnit is relatively quite expensive;
the default constructor is a far cheaper way to initialize a LayoutUnit
with the value of 0.

Implicit conversions from int to LayoutUnit mean that tests against 0
are also surprisingly expensive.

* Source/WebCore/platform/graphics/LayoutPoint.h: Modify 'LayoutPoint()' to default constructor
* Source/WebCore/platform/graphics/LayoutSize.h:
(1) Modify 'LayoutPoint()' to default constructor
(2) bool 'isEmpty' to return values with "rawValues()"

Canonical link: https://commits.webkit.org/259177@main