Add support for the object-fit CSS property.

Source/core/platform/graphics/LayoutSize.h

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 152 matching lines @@
 inline IntSize roundedIntSize(const LayoutSize& s)
 {
     return IntSize(s.width().round(), s.height().round());
 }
 
 inline LayoutSize roundedLayoutSize(const FloatSize& s)
 {
     return LayoutSize(s);
 }
 
+// Convert the specified scaled size to one that agrees with the specified aspect ratio
+// (expressed as a size, too).

[ojan, 2013/08/08 02:36:55]

Blink (and WebKit) style is to leave out "what" comments that say what the code
does. Comments are for "why" explanations and for high-level descriptions (e.g.
discussing how a class is intended to be used).

I think all these comment (including the one in fitLayoutSizeToAspectRatio) just
say what the code obviously does, so they can be left out.

[mstensho (USE GERRIT), 2013/08/08 07:26:42]

Done.

+enum AspectRatioFit { // How to set a size with the specified aspect ratio
+    AspectRatioFitShrink, // Shrink in one dimension to gain aspect ratio
+    AspectRatioFitGrow // Grow in one dimension to gain aspect ratio
+};

[ojan, 2013/08/08 02:36:55]

Needs another line-break here.

[mstensho (USE GERRIT), 2013/08/08 07:26:42]

Done.

+inline LayoutSize fitLayoutSizeToAspectRatio(const LayoutSize& scaledSize, const LayoutSize& aspectRatio, AspectRatioFit fit)

[ojan, 2013/08/08 02:36:55]

I think this method makes more sense as a member of LayoutSize. It's similar to
expandedTo or transposedSize.

[mstensho (USE GERRIT), 2013/08/08 07:26:42]

Done.

+{
+    // Set a new width or height to get to a size that honors the aspect ratio. If fit is
+    // AspectRatioFitGrow, increase in the dimension that is scaled less. Otherwise,
+    // decrease in the dimension that is scaled more.
+    float heightScale = scaledSize.height().toFloat() / aspectRatio.height().toFloat();
+    float widthScale = scaledSize.width().toFloat() / aspectRatio.width().toFloat();
+    if ((widthScale > heightScale) != (fit == AspectRatioFitGrow))
+        return LayoutSize(scaledSize.height() * aspectRatio.width() / aspectRatio.height(), scaledSize.height());
+    return LayoutSize(scaledSize.width(), scaledSize.width() * aspectRatio.height() / aspectRatio.width());
+}
+
 } // namespace WebCore
 
 #endif // LayoutSize_h