Adding the 'filter' context attribute to 2D canvas

Source/core/paint/FilterEffectBuilder.h

Index: Source/core/paint/FilterEffectBuilder.h
diff --git a/Source/core/paint/FilterEffectBuilder.h b/Source/core/paint/FilterEffectBuilder.h
index 4c4bed223b0c556002628123a8693bb88a71b5c4..47482ab2d7e3b29ebb9a6ce42e2c4dd6db6c80d7 100644
--- a/Source/core/paint/FilterEffectBuilder.h
+++ b/Source/core/paint/FilterEffectBuilder.h
@@ -37,7 +37,7 @@ namespace blink {
 
 class FilterOperations;
 class ReferenceFilter;
-class LayoutObject;
+class Element;
 
 class FilterEffectBuilder final : public RefCountedWillBeGarbageCollectedFinalized<FilterEffectBuilder> {
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(FilterEffectBuilder);
@@ -50,7 +50,12 @@ public:
     virtual ~FilterEffectBuilder();
     DECLARE_TRACE();
 
-    bool build(LayoutObject*, const FilterOperations&);
+    enum ScaleMode {
+        ApplyScale,

[Stephen White, 2015/06/22 15:28:54]

<bikedshed> Since this uses the effectiveZoom(), we should call these ApplyZoom
and IgnoreZoom. </bikeshed>

Or maybe we should just pass in a (float) zoom value, and let the caller figure
it out.

+        IgnoreScale,
+    };
+
+    bool build(Element*, const FilterOperations&, ScaleMode);
 
     PassRefPtrWillBeRawPtr<FilterEffect> lastEffect() const
     {