Implement accessibility support for CSS-transformed iframes.

third_party/WebKit/public/web/WebAXObject.h

Index: third_party/WebKit/public/web/WebAXObject.h
diff --git a/third_party/WebKit/public/web/WebAXObject.h b/third_party/WebKit/public/web/WebAXObject.h
index b591739a1cb33a8f9ae5617a9855593d2da4b6c5..9af1b22288861ab1a34f9ea9937221d241bbbd8c 100644
--- a/third_party/WebKit/public/web/WebAXObject.h
+++ b/third_party/WebKit/public/web/WebAXObject.h
@@ -42,6 +42,8 @@
 namespace WTF { template <typename T> class PassRefPtr; }
 #endif
 
+class SkMatrix44;
+
 namespace blink {
 
 class AXObject;
@@ -282,6 +284,9 @@ public:
     BLINK_EXPORT WebPoint maximumScrollOffset() const;
     BLINK_EXPORT void setScrollOffset(const WebPoint&) const;
 
+    // Transformation relative to the parent frame, if local (otherwise returns identity).
+    BLINK_EXPORT SkMatrix44 transformFromLocalParentFrame() const;
+
     // Make this object visible by scrolling as many nested scrollable views as needed.
     BLINK_EXPORT void scrollToMakeVisible() const;
     // Same, but if the whole object can't be made visible, try for this subrect, in local coordinates.