Animated scroll shouldn't consume unhandled scrolls for OOPIFs.

content/browser/renderer_host/compositor_impl_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/compositor_impl_android.h"
 
 #include <android/bitmap.h>
 #include <android/native_window_jni.h>
 #include <stdint.h>
 #include <unordered_set>
@@ skipping 433 matching lines @@
 }
 
 CompositorImpl::~CompositorImpl() {
   root_window_->DetachCompositor();
   root_window_->SetLayer(nullptr);
   // Clean-up any surface references.
   SetSurface(NULL);
   GetSurfaceManager()->InvalidateFrameSinkId(frame_sink_id_);
 }
 
+bool CompositorImpl::IsForSubframe() {
+  return false;

[Charlie Reis, 2017/04/18 21:59:03]

I'm not familiar with this class, but would this cause a problem for OOPIFs on
Android?  Or do those not have one of these?

[wjmaclean, 2017/04/18 23:26:49]

I think, at worst, it leaves the status quo unchanged for Android. I don't think
Android uses smooth scrolling for mouse wheels, or other 'bubbling' events ... I
could be wrong though, in which case this might be the starting point to deal
with that.

+}
+
 ui::UIResourceProvider& CompositorImpl::GetUIResourceProvider() {
   return *this;
 }
 
 ui::ResourceManager& CompositorImpl::GetResourceManager() {
   return resource_manager_;
 }
 
 void CompositorImpl::SetRootLayer(scoped_refptr<cc::Layer> root_layer) {
   if (subroot_layer_.get()) {
@@ skipping 405 matching lines @@
   }
   GetSurfaceManager()->UnregisterFrameSinkHierarchy(frame_sink_id_,
                                                     frame_sink_id);
 }
 
 bool CompositorImpl::HavePendingReadbacks() {
   return !readback_layer_tree_->children().empty();
 }
 
 }  // namespace content