Implement accessibility support for CSS-transformed iframes.

third_party/WebKit/Source/modules/accessibility/AXObject.h

Index: third_party/WebKit/Source/modules/accessibility/AXObject.h
diff --git a/third_party/WebKit/Source/modules/accessibility/AXObject.h b/third_party/WebKit/Source/modules/accessibility/AXObject.h
index d6e4de96cde99f5ece1e4e2ba29ca6e78c227cf0..52124d8173af79e21571a21b654d1cf559f9dcd6 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObject.h
+++ b/third_party/WebKit/Source/modules/accessibility/AXObject.h
@@ -39,6 +39,8 @@
 #include "wtf/Forward.h"
 #include "wtf/Vector.h"
 
+class SkMatrix44;
+
 namespace blink {
 
 class AXObject;
@@ -791,6 +793,9 @@ public:
     virtual void markCachedElementRectDirty() const;
     virtual IntPoint clickPoint();
 
+    // Transform relative to the local frame root.
+    virtual SkMatrix44 localFrameRootTransform() const;
+
     // Hit testing.
     // Called on the root AX object to return the deepest available element.
     virtual AXObject* accessibilityHitTest(const IntPoint&) const { return 0; }