(WIP) Paint property hierarchy approach 1 of 2

third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h

Index: third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h b/third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h
index 69a6651de7ed9dc39f562fcb2b79e711512dbbb6..31c8b34241796b65cc3fe60f1ff16c9d37061e10 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h
@@ -9,17 +9,19 @@
 
 namespace blink {
 
-// The set of paint properties applying to a |PaintChunk|.
-// In particular, this does not mean properties like background-color, but
-// rather the hierarchy of transforms, clips, effects, etc. that apply to a
-// contiguous chunk of drawings.
+// The set of paint properties applying to a |PaintChunk|. Each property index
+// maps back to a paint property in the |PaintArtifact|'s property vectors.
+// These properties are not simple color changes but instead represent the
+// hierachy of transforms, clips, effects, etc, that apply to a contiguous
+// chunk of display items.
 struct PaintProperties {
-    // TODO(jbroman): Add actual properties.
+    // TODO(pdr): Add clip, scroll, and effect property indices.
+    size_t transformIndex;
 };
 
-inline bool operator==(const PaintProperties&, const PaintProperties&)
+inline bool operator==(const PaintProperties& a, const PaintProperties& b)
 {
-    return true;
+    return a.transformIndex == b.transformIndex;
 }
 
 inline bool operator!=(const PaintProperties& a, const PaintProperties& b)