Animated scroll shouldn't require main-frame for OOPIFs.

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 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/renderer/gpu/render_widget_compositor.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 211 matching lines @@
 
 // static
 std::unique_ptr<cc::LayerTreeHost> RenderWidgetCompositor::CreateLayerTreeHost(
     LayerTreeHostClient* client,
     cc::LayerTreeHostSingleThreadClient* single_thread_client,
     cc::MutatorHost* mutator_host,
     CompositorDependencies* deps,
     float device_scale_factor,
     const ScreenInfo& screen_info) {
   base::CommandLine* cmd = base::CommandLine::ForCurrentProcess();
-  cc::LayerTreeSettings settings =
-      GenerateLayerTreeSettings(*cmd, deps, device_scale_factor, screen_info);
+  cc::LayerTreeSettings settings = GenerateLayerTreeSettings(
+      *cmd, deps, device_scale_factor, client->IsForSubframe(), screen_info);
 
   const bool is_threaded = !!deps->GetCompositorImplThreadTaskRunner();
 
   std::unique_ptr<cc::LayerTreeHost> layer_tree_host;
 
   cc::LayerTreeHost::InitParams params;
   params.client = client;
   params.settings = &settings;
   params.task_graph_runner = deps->GetTaskGraphRunner();
   params.main_task_runner = deps->GetCompositorMainThreadTaskRunner();
@@ skipping 19 matching lines @@
   }
 
   return layer_tree_host;
 }
 
 // static
 cc::LayerTreeSettings RenderWidgetCompositor::GenerateLayerTreeSettings(
     const base::CommandLine& cmd,
     CompositorDependencies* compositor_deps,
     float device_scale_factor,
+    bool is_for_subframe,
     const ScreenInfo& screen_info) {
   cc::LayerTreeSettings settings;
 
+  settings.is_layer_tree_for_subframe = is_for_subframe;
+
   // For web contents, layer transforms should scale up the contents of layers
   // to keep content always crisp when possible.
   settings.layer_transforms_should_scale_layer_contents = true;
 
   settings.main_frame_before_activation_enabled =
       cmd.HasSwitch(cc::switches::kEnableMainFrameBeforeActivation);
 
   settings.enable_checker_imaging =
       cmd.HasSwitch(cc::switches::kEnableCheckerImaging);
 
@@ skipping 824 matching lines @@
 }
 
 void RenderWidgetCompositor::DidReceiveCompositorFrameAck() {
   delegate_->DidReceiveCompositorFrameAck();
 }
 
 void RenderWidgetCompositor::DidCompletePageScaleAnimation() {
   delegate_->DidCompletePageScaleAnimation();
 }
 
+bool RenderWidgetCompositor::IsForSubframe() {
+  return is_for_oopif_;
+}
+
 void RenderWidgetCompositor::RequestScheduleAnimation() {
   delegate_->RequestScheduleAnimation();
 }
 
 void RenderWidgetCompositor::DidSubmitCompositorFrame() {}
 
 void RenderWidgetCompositor::DidLoseCompositorFrameSink() {}
 
 void RenderWidgetCompositor::SetFrameSinkId(
     const cc::FrameSinkId& frame_sink_id) {
@@ skipping 17 matching lines @@
 void RenderWidgetCompositor::SetContentSourceId(uint32_t id) {
   layer_tree_host_->SetContentSourceId(id);
 }
 
 void RenderWidgetCompositor::SetLocalSurfaceId(
     const cc::LocalSurfaceId& local_surface_id) {
   layer_tree_host_->SetLocalSurfaceId(local_surface_id);
 }
 
 }  // namespace content