Fix subpixel accumulation for composited content layers

third_party/WebKit/Source/core/layout/LayoutTextTrackContainer.cpp

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 41 matching lines @@
     if (updateSizes(toLayoutVideo(*mediaLayoutObject)))
         toElement(node())->setInlineStyleProperty(CSSPropertyFontSize, m_fontSize, CSSPrimitiveValue::UnitType::Pixels);
 }
 
 bool LayoutTextTrackContainer::updateSizes(const LayoutVideo& videoLayoutObject)
 {
     // FIXME: The video size is used to calculate the font size (a workaround
     // for lack of per-spec vh/vw support) but the whole media element is used
     // for cue rendering. This is inconsistent. See also the somewhat related
     // spec bug: https://www.w3.org/Bugs/Public/show_bug.cgi?id=28105
-    IntSize videoSize = videoLayoutObject.videoBox().size();

[chrishtr, 2016/07/21 18:02:31]

Why the changes here? videoBox() has integer size.

-    if (m_videoSize == videoSize)
-        return false;
-    m_videoSize = videoSize;
+    LayoutSize videoSize = videoLayoutObject.videoBox().size();
 
-    float smallestDimension = std::min(m_videoSize.height(), m_videoSize.width());
+    float smallestDimension = std::min(videoSize.height(), videoSize.width()).toFloat();
 
     float fontSize = smallestDimension * 0.05f;
     if (m_fontSize == fontSize)
         return false;
     m_fontSize = fontSize;
     return true;
 }
 
 } // namespace blink