p1 mus+ash chrome renders ui and content

ui/views/mus/native_widget_mus.cc

 // Copyright 2015 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 "ui/views/mus/native_widget_mus.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "components/mus/public/cpp/property_type_converters.h"
 #include "components/mus/public/cpp/window.h"
 #include "mojo/converters/geometry/geometry_type_converters.h"
@@ skipping 241 matching lines @@
 void NativeWidgetMus::InitNativeWidget(const Widget::InitParams& params) {
   ownership_ = params.ownership;
   window_->SetCanFocus(params.activatable ==
                        Widget::InitParams::ACTIVATABLE_YES);
 
   // WindowTreeHost creates the compositor using the ContextFactory from
   // aura::Env. Install |context_factory_| there so that |context_factory_| is
   // picked up.
   ui::ContextFactory* default_context_factory =
       aura::Env::GetInstance()->context_factory();
-  aura::Env::GetInstance()->set_context_factory(context_factory_.get());
+  // For Chrome, we need the GpuProcessTransportFactory so that renderer and
+  // browser pixels are composited into a single backing
+  // SoftwareOutputDeviceMus.
+  if (!default_context_factory)
+    aura::Env::GetInstance()->set_context_factory(context_factory_.get());
   window_tree_host_.reset(
       new WindowTreeHostMus(shell_, this, window_, surface_type_));
   window_tree_host_->InitHost();
   aura::Env::GetInstance()->set_context_factory(default_context_factory);
-  DCHECK_EQ(context_factory_.get(),
-            window_tree_host_->compositor()->context_factory());
 
   focus_client_.reset(new wm::FocusController(new FocusRulesImpl));
 
   aura::client::SetFocusClient(window_tree_host_->window(),
                                focus_client_.get());
   aura::client::SetActivationClient(window_tree_host_->window(),
                                     focus_client_.get());
   window_tree_client_.reset(
       new NativeWidgetMusWindowTreeClient(window_tree_host_->window()));
   window_tree_host_->window()->AddPreTargetHandler(focus_client_.get());
@@ skipping 491 matching lines @@
   } else {
     native_widget_delegate_->OnScrollEvent(event);
   }
 }
 
 void NativeWidgetMus::OnGestureEvent(ui::GestureEvent* event) {
   native_widget_delegate_->OnGestureEvent(event);
 }
 
 }  // namespace views