Extract shell methods from ApplicationImpl into a base class, and pass this to Initialize() instead.

ui/views/mus/surface_context_factory.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/surface_context_factory.h"
 
 #include "cc/output/output_surface.h"
 #include "cc/resources/shared_bitmap_manager.h"
 #include "cc/surfaces/surface_id_allocator.h"
 #include "components/mus/public/cpp/window.h"
 #include "mojo/shell/public/interfaces/shell.mojom.h"
 #include "ui/compositor/reflector.h"
 #include "ui/gl/gl_bindings.h"
 
 namespace views {
 namespace {
 
 class FakeReflector : public ui::Reflector {
  public:
   FakeReflector() {}
   ~FakeReflector() override {}
   void OnMirroringCompositorResized() override {}
   void AddMirroringLayer(ui::Layer* layer) override {}
   void RemoveMirroringLayer(ui::Layer* layer) override {}
 };
 
 }  // namespace
 
 SurfaceContextFactory::SurfaceContextFactory(
-    mojo::shell::mojom::Shell* shell,
+    mojo::Shell* shell,
     mus::Window* window,
     mus::mojom::SurfaceType surface_type)
     : surface_binding_(shell, window, surface_type),
       next_surface_id_namespace_(1u) {}
 
 SurfaceContextFactory::~SurfaceContextFactory() {}
 
 void SurfaceContextFactory::CreateOutputSurface(
     base::WeakPtr<ui::Compositor> compositor) {
   // NOTIMPLEMENTED();
@@ skipping 50 matching lines @@
   return make_scoped_ptr(
       new cc::SurfaceIdAllocator(next_surface_id_namespace_++));
 }
 
 void SurfaceContextFactory::ResizeDisplay(ui::Compositor* compositor,
                                           const gfx::Size& size) {
   // NOTIMPLEMENTED();
 }
 
 }  // namespace views