Move handling of DraggableRegionsChanged notification from "view" to "frame".

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 9a8d0e84e6791203c525d5874c96bfda1af37a74..75be6c201513eab17160bc1bb0e707a96837dd04 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -6631,6 +6631,11 @@ std::unique_ptr<blink::WebURLLoader> RenderFrameImpl::CreateURLLoader() {
   return blink::Platform::Current()->CreateURLLoader();
 }
 
+void RenderFrameImpl::DraggableRegionsChanged() {
+  for (auto& observer : observers_)
+    observer.DraggableRegionsChanged();
+}
+
 blink::WebPageVisibilityState RenderFrameImpl::GetVisibilityState() const {
   return VisibilityState();
 }