Hookup android_webview scroll offset delegation to Java side.

ui/gfx/vector2d_f.h

Index: ui/gfx/vector2d_f.h
diff --git a/ui/gfx/vector2d_f.h b/ui/gfx/vector2d_f.h
index fdd3a9e30841cc0681ebaf509d0a9d1ba17dde4a..4faf28ae2262a0c949c0e38e4a2c8f85a3a28771 100644
--- a/ui/gfx/vector2d_f.h
+++ b/ui/gfx/vector2d_f.h
@@ -70,6 +70,10 @@ inline bool operator==(const Vector2dF& lhs, const Vector2dF& rhs) {
   return lhs.x() == rhs.x() && lhs.y() == rhs.y();
 }
 
+inline bool operator!=(const Vector2dF& lhs, const Vector2dF& rhs) {
+  return !(lhs == rhs);
+}
+
 inline Vector2dF operator-(const Vector2dF& v) {
   return Vector2dF(-v.x(), -v.y());
 }