Remove compositing trigger for will-change: top (and similar)

Source/core/rendering/style/RenderStyle.cpp

Index: Source/core/rendering/style/RenderStyle.cpp
diff --git a/Source/core/rendering/style/RenderStyle.cpp b/Source/core/rendering/style/RenderStyle.cpp
index 108339c9af80506244571f5352c84493cfd3ac93..3e45a0ccd4d2b73bbc1d4b1b49422349f1c5af40 100644
--- a/Source/core/rendering/style/RenderStyle.cpp
+++ b/Source/core/rendering/style/RenderStyle.cpp
@@ -869,11 +869,6 @@ bool RenderStyle::hasWillChangeCompositingHint() const
         case CSSPropertyOpacity:
         case CSSPropertyTransform:
         case CSSPropertyWebkitTransform:
-        case CSSPropertyLeft:
-        case CSSPropertyTop:
-        case CSSPropertyRight:
-        case CSSPropertyBottom:
-        case CSSPropertyWebkitFilter:

[ajuma, 2014/05/07 20:16:43]

Are these removals still needed for correctness given the changes made to layer
creation logic in RenderBox and RenderTableRow? Since we now never specifically
create RenderLayers for will-change hints, there seems to be no harm leaving
these in (since they'll only cause already-existing layers to composite).

[abarth-chromium, 2014/05/07 20:19:59]

As I wrote in the change description, I think we should restore the system to
correctness and then possibly re-introduce these compositing triggers in the
future.  Currently they don't work.

             return true;
         default:
             break;