Reland of "Mustash: Ensure surfaces submitted to Mus by WM and embedders...

Reland of "Mustash: Ensure surfaces submitted to Mus by WM and embedders contain Surfaces with embeded content."

- Use SurfaceLayers in embedders and Window Manager to properly position
  the embedded content in the layer tree.

- WM no longer uses underlay surfaces for window decorations. Instead
  they are submitted to Mus as part of the WM's surface.

- FrameGenerator now only creates SurfaceDrawQuad for the top-level
  window rather than recursively creating SurfaceDrawQuad for all windows
  in the window tree, since all surfaces are now part of the tree rooted
  at the surface of the top-level window.

Previously landed in crrev.com/441492, but reverted in crrev.com/441522
since it broke some tests on Windows. This CL includes a fix for that
brokenness.

BUG=672943, 669964
TBR=jbauman@ for DEPS change (previously lgtm'ed in the original CL)

Review-Url: https://codereview.chromium.org/2613903003
Cr-Commit-Position: refs/heads/master@{#441753}

services/ui/ws/display.cc

@@ -271,6 +271,13 @@ ServerWindow* Display::GetRootWindow() {
   return root_.get();
 }
 
+ServerWindow* Display::GetActiveRootWindow() {
+  WindowManagerDisplayRoot* display_root = GetActiveWindowManagerDisplayRoot();
+  if (display_root)
+    return display_root->root();
+  return nullptr;
+}
+
 void Display::OnAcceleratedWidgetAvailable() {
   display_manager()->OnDisplayAcceleratedWidgetAvailable(this);
   InitWindowManagerDisplayRoots();

services/ui/ws/display.h

@@ -166,6 +166,7 @@ class Display : public PlatformDisplayDelegate,
   // PlatformDisplayDelegate:
   display::Display GetDisplay() override;
   ServerWindow* GetRootWindow() override;
+  ServerWindow* GetActiveRootWindow() override;
   void OnAcceleratedWidgetAvailable() override;
   bool IsInHighContrastMode() override;
   void OnEvent(const ui::Event& event) override;

services/ui/ws/frame_generator.cc

@@ -130,7 +130,7 @@ cc::CompositorFrame FrameGenerator::GenerateCompositorFrame(
   render_pass->SetNew(render_pass_id, output_rect, output_rect,
                       gfx::Transform());
 
-  DrawWindowTree(render_pass.get(), root_window_, gfx::Vector2d(), 1.0f);
+  DrawWindow(render_pass.get(), delegate_->GetActiveRootWindow());
 
   cc::CompositorFrame frame;
   frame.render_pass_list.push_back(std::move(render_pass));
@@ -155,80 +155,40 @@ cc::CompositorFrame FrameGenerator::GenerateCompositorFrame(
   return frame;
 }
 
-void FrameGenerator::DrawWindowTree(
-    cc::RenderPass* pass,
-    ServerWindow* window,
-    const gfx::Vector2d& parent_to_root_origin_offset,
-    float opacity) {
-  if (!window->visible())
+void FrameGenerator::DrawWindow(cc::RenderPass* pass, ServerWindow* window) {
+  if (!window || !window->visible())
     return;
 
-  const gfx::Rect absolute_bounds =
-      window->bounds() + parent_to_root_origin_offset;
-  const ServerWindow::Windows& children = window->children();
-  const float combined_opacity = opacity * window->opacity();
-  for (ServerWindow* child : base::Reversed(children)) {
-    DrawWindowTree(pass, child, absolute_bounds.OffsetFromOrigin(),
-                   combined_opacity);
-  }
-
   if (!window->compositor_frame_sink_manager() ||
       !window->compositor_frame_sink_manager()->ShouldDraw())
     return;
 
-  cc::SurfaceId underlay_surface_id =
-      window->compositor_frame_sink_manager()->GetLatestSurfaceId(
-          mojom::CompositorFrameSinkType::UNDERLAY);
   cc::SurfaceId default_surface_id =
       window->compositor_frame_sink_manager()->GetLatestSurfaceId(
           mojom::CompositorFrameSinkType::DEFAULT);
 
-  if (!underlay_surface_id.is_valid() && !default_surface_id.is_valid())
+  if (!default_surface_id.is_valid())
     return;
 
-  if (default_surface_id.is_valid()) {
-    gfx::Transform quad_to_target_transform;
-    quad_to_target_transform.Translate(absolute_bounds.x(),
-                                       absolute_bounds.y());
-
-    cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
-
-    const gfx::Rect bounds_at_origin(window->bounds().size());
-    // TODO(fsamuel): These clipping and visible rects are incorrect. They need
-    // to be populated from CompositorFrame structs.
-    sqs->SetAll(
-        quad_to_target_transform, bounds_at_origin.size() /* layer_bounds */,
-        bounds_at_origin /* visible_layer_bounds */,
-        bounds_at_origin /* clip_rect */, false /* is_clipped */,
-        combined_opacity, SkBlendMode::kSrcOver, 0 /* sorting-context_id */);
-    auto* quad = pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
-    quad->SetAll(sqs, bounds_at_origin /* rect */,
-                 gfx::Rect() /* opaque_rect */,
-                 bounds_at_origin /* visible_rect */, true /* needs_blending*/,
-                 default_surface_id);
-  }
-  if (underlay_surface_id.is_valid()) {
-    const gfx::Rect underlay_absolute_bounds =
-        absolute_bounds - window->underlay_offset();
-    gfx::Transform quad_to_target_transform;
-    quad_to_target_transform.Translate(underlay_absolute_bounds.x(),
-                                       underlay_absolute_bounds.y());
-    cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
-    const gfx::Rect bounds_at_origin(
-        window->compositor_frame_sink_manager()->GetLatestFrameSize(
-            mojom::CompositorFrameSinkType::UNDERLAY));
-    sqs->SetAll(
-        quad_to_target_transform, bounds_at_origin.size() /* layer_bounds */,
-        bounds_at_origin /* visible_layer_bounds */,
-        bounds_at_origin /* clip_rect */, false /* is_clipped */,
-        combined_opacity, SkBlendMode::kSrcOver, 0 /* sorting-context_id */);
-
-    auto* quad = pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
-    quad->SetAll(sqs, bounds_at_origin /* rect */,
-                 gfx::Rect() /* opaque_rect */,
-                 bounds_at_origin /* visible_rect */, true /* needs_blending*/,
-                 underlay_surface_id);
-  }
+  gfx::Transform quad_to_target_transform;
+  quad_to_target_transform.Translate(window->bounds().x(),
+                                     window->bounds().y());
+
+  cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
+
+  const gfx::Rect bounds_at_origin(window->bounds().size());
+  // TODO(fsamuel): These clipping and visible rects are incorrect. They need
+  // to be populated from CompositorFrame structs.
+  sqs->SetAll(
+      quad_to_target_transform, bounds_at_origin.size() /* layer_bounds */,
+      bounds_at_origin /* visible_layer_bounds */,
+      bounds_at_origin /* clip_rect */, false /* is_clipped */,
+      1.0f /* opacity */, SkBlendMode::kSrcOver, 0 /* sorting-context_id */);
+  auto* quad = pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
+  quad->SetAll(sqs, bounds_at_origin /* rect */,
+               gfx::Rect() /* opaque_rect */,
+               bounds_at_origin /* visible_rect */, true /* needs_blending*/,
+               default_surface_id);
 }
 
 cc::SurfaceId FrameGenerator::FindParentSurfaceId(ServerWindow* window) {

services/ui/ws/frame_generator.h

@@ -80,12 +80,9 @@ class FrameGenerator : public ServerWindowTracker,
   // Generates the CompositorFrame.
   cc::CompositorFrame GenerateCompositorFrame(const gfx::Rect& output_rect);
 
-  // DrawWindowTree recursively visits ServerWindows, creating a SurfaceDrawQuad
-  // for each that lacks one.
-  void DrawWindowTree(cc::RenderPass* pass,
-                      ServerWindow* window,
-                      const gfx::Vector2d& parent_to_root_origin_offset,
-                      float opacity);
+  // DrawWindow creates SurfaceDrawQuad for the provided ServerWindow and
+  // appends it to the provided cc::RenderPass.
+  void DrawWindow(cc::RenderPass* pass, ServerWindow* window);
 
   // Finds the parent surface id for |window|.
   cc::SurfaceId FindParentSurfaceId(ServerWindow* window);

services/ui/ws/frame_generator_delegate.h

@@ -10,6 +10,8 @@ namespace ws {
 
 class FrameGeneratorDelegate {
  public:
+  // Returns the root window of the active user.
+  virtual ServerWindow* GetActiveRootWindow() = 0;
   virtual bool IsInHighContrastMode() = 0;
 
  protected:

services/ui/ws/frame_generator_unittest.cc

@@ -52,8 +52,8 @@ class FrameGeneratorTest : public testing::Test {
                                                     kRootDisplayId)) {}
   ~FrameGeneratorTest() override {}
 
-  // Calls DrawWindowTree() on |frame_generator_|
-  void DrawWindowTree(cc::RenderPass* pass);
+  // Calls DrawWindow() on |frame_generator_|
+  void DrawWindow(cc::RenderPass* pass);
 
   ServerWindow* root_window() { return root_window_.get(); }
 
@@ -75,14 +75,14 @@ class FrameGeneratorTest : public testing::Test {
   DISALLOW_COPY_AND_ASSIGN(FrameGeneratorTest);
 };
 
-void FrameGeneratorTest::DrawWindowTree(cc::RenderPass* pass) {
-  frame_generator_->DrawWindowTree(pass, root_window_.get(), gfx::Vector2d(),
-                                   1.0f);
+void FrameGeneratorTest::DrawWindow(cc::RenderPass* pass) {
+  frame_generator_->DrawWindow(pass, root_window_.get());
 }
 
 void FrameGeneratorTest::SetUp() {
   testing::Test::SetUp();
-  frame_generator_delegate_ = base::MakeUnique<TestFrameGeneratorDelegate>();
+  frame_generator_delegate_ =
+      base::MakeUnique<TestFrameGeneratorDelegate>(root_window_.get());
   PlatformDisplayInitParams init_params;
   frame_generator_ = base::MakeUnique<FrameGenerator>(
       frame_generator_delegate_.get(), root_window_.get());
@@ -97,51 +97,23 @@ void FrameGeneratorTest::TearDown() {
 }
 
 // Tests correctness of the SharedQuadStateList generated by
-// FrameGenerator::DrawWindowTree().
-TEST_F(FrameGeneratorTest, DrawWindowTree) {
+// FrameGenerator::DrawWindow().
+TEST_F(FrameGeneratorTest, DrawWindow) {
   ServerWindow child_window(test_window_delegate(), WindowId(1, 1));
   root_window()->Add(&child_window);
   InitWindow(&child_window);
-  const float root_opacity = .5f;
   const float child_opacity = .4f;
-  root_window()->SetOpacity(root_opacity);
   child_window.SetOpacity(child_opacity);
 
   std::unique_ptr<cc::RenderPass> render_pass = cc::RenderPass::Create();
-  DrawWindowTree(render_pass.get());
+  DrawWindow(render_pass.get());
   cc::SharedQuadStateList* quad_state_list =
       &render_pass->shared_quad_state_list;
 
-  // Both child and root have a DEFAULT Surface and no underlay Surfaces, so
-  // there should be two SharedQuadStates in the list.
-  EXPECT_EQ(2u, quad_state_list->size());
+  EXPECT_EQ(1u, quad_state_list->size());
   cc::SharedQuadState* root_sqs = quad_state_list->back();
-  cc::SharedQuadState* child_sqs = quad_state_list->front();
-  EXPECT_EQ(root_opacity, root_sqs->opacity);
-  // Child's SharedQuadState contains the effective opacity of the child layer,
-  // which should be a product of the child and the parent opacity.
-  EXPECT_EQ(child_opacity * root_opacity, child_sqs->opacity);
-
-  // Pretend to create the UNDERLAY Surface for the child window, and confirm
-  // that this creates an extra SharedQuadState in the CompositorFrame.
-  child_window.GetOrCreateCompositorFrameSinkManager()->SetLatestSurfaceInfo(
-      mojom::CompositorFrameSinkType::UNDERLAY,
-      cc::SurfaceInfo(
-          cc::SurfaceId(
-              cc::FrameSinkId(WindowIdToTransportId(child_window.id()),
-                              static_cast<uint32_t>(
-                                  mojom::CompositorFrameSinkType::UNDERLAY)),
-              cc::LocalFrameId(1u, kArbitraryToken)),
-          1.0f, gfx::Size(100, 100)));
-
-  render_pass = cc::RenderPass::Create();
-  DrawWindowTree(render_pass.get());
-  quad_state_list = &render_pass->shared_quad_state_list;
-  EXPECT_EQ(3u, quad_state_list->size());
-  auto it = quad_state_list->begin();
-  EXPECT_EQ(child_opacity * root_opacity, (*it)->opacity);
-  EXPECT_EQ(child_opacity * root_opacity, (*++it)->opacity);
-  EXPECT_EQ(root_opacity, (*++it)->opacity);
+  // Opacity should always be 1.
+  EXPECT_EQ(1.0f, root_sqs->opacity);
 }
 
 }  // namespace test

services/ui/ws/platform_display_default.cc

@@ -248,6 +248,10 @@ void PlatformDisplayDefault::OnAcceleratedWidgetDestroyed() {
 
 void PlatformDisplayDefault::OnActivationChanged(bool active) {}
 
+ServerWindow* PlatformDisplayDefault::GetActiveRootWindow() {
+  return delegate_->GetActiveRootWindow();
+}
+
 bool PlatformDisplayDefault::IsInHighContrastMode() {
   return delegate_ ? delegate_->IsInHighContrastMode() : false;
 }

services/ui/ws/platform_display_default.h

@@ -68,6 +68,7 @@ class PlatformDisplayDefault : public PlatformDisplay,
   void OnActivationChanged(bool active) override;
 
   // FrameGeneratorDelegate:
+  ServerWindow* GetActiveRootWindow() override;
   bool IsInHighContrastMode() override;
 
   const int64_t display_id_;

services/ui/ws/platform_display_delegate.h

@@ -28,6 +28,9 @@ class PlatformDisplayDelegate {
   // Returns the root window of this display.
   virtual ServerWindow* GetRootWindow() = 0;
 
+  // Returns the root window of the active user.
+  virtual ServerWindow* GetActiveRootWindow() = 0;
+
   // Called once when the AcceleratedWidget is available for drawing.
   virtual void OnAcceleratedWidgetAvailable() = 0;
 

services/ui/ws/server_window_compositor_frame_sink_manager.cc

@@ -29,9 +29,7 @@ bool ServerWindowCompositorFrameSinkManager::ShouldDraw() {
     return true;
 
   waiting_for_initial_frames_ = !IsCompositorFrameSinkReadyAndNonEmpty(
-                                    mojom::CompositorFrameSinkType::DEFAULT) ||
-                                !IsCompositorFrameSinkReadyAndNonEmpty(
-                                    mojom::CompositorFrameSinkType::UNDERLAY);
+      mojom::CompositorFrameSinkType::DEFAULT);
   return !waiting_for_initial_frames_;
 }
 

services/ui/ws/server_window_compositor_frame_sink_manager.h

@@ -109,6 +109,8 @@ class ServerWindowCompositorFrameSinkManager {
 
   TypeToCompositorFrameSinkMap type_to_compositor_frame_sink_map_;
 
+  // TODO(mfomitchev): This is currently always false. Confirm if we still need
+  // this.
   // While true the window is not drawn. This is initially true if the window
   // has the property |kWaitForUnderlay_Property|. This is set to false once
   // the underlay and default surface have been set *and* their size is at

services/ui/ws/test_utils.cc

@@ -151,10 +151,16 @@ TestPlatformDisplayFactory::CreatePlatformDisplay(
 
 // TestFrameGeneratorDelegate -------------------------------------------------
 
-TestFrameGeneratorDelegate::TestFrameGeneratorDelegate() {}
+TestFrameGeneratorDelegate::TestFrameGeneratorDelegate(
+    ServerWindow* root_window)
+    : root_window_(root_window) {}
 
 TestFrameGeneratorDelegate::~TestFrameGeneratorDelegate() {}
 
+ServerWindow* TestFrameGeneratorDelegate::GetActiveRootWindow() {
+  return root_window_;
+}
+
 bool TestFrameGeneratorDelegate::IsInHighContrastMode() {
   return false;
 }

services/ui/ws/test_utils.h

@@ -285,13 +285,16 @@ class TestPlatformDisplayFactory : public PlatformDisplayFactory {
 // A stub implementation of FrameGeneratorDelegate.
 class TestFrameGeneratorDelegate : public FrameGeneratorDelegate {
  public:
-  TestFrameGeneratorDelegate();
+  TestFrameGeneratorDelegate(ServerWindow* root_window);
   ~TestFrameGeneratorDelegate() override;
 
   // FrameGeneratorDelegate:
+  ServerWindow* GetActiveRootWindow() override;
   bool IsInHighContrastMode() override;
 
  private:
+  ServerWindow* root_window_;
+
   DISALLOW_COPY_AND_ASSIGN(TestFrameGeneratorDelegate);
 };
 

ui/aura/BUILD.gn

@@ -71,6 +71,8 @@ component("aura") {
     "mus/capture_synchronizer.cc",
     "mus/capture_synchronizer.h",
     "mus/capture_synchronizer_delegate.h",
+    "mus/client_surface_embedder.cc",
+    "mus/client_surface_embedder.h",
     "mus/drag_drop_controller_host.h",
     "mus/drag_drop_controller_mus.cc",
     "mus/drag_drop_controller_mus.h",

ui/aura/mus/DEPS

@@ -6,6 +6,7 @@ include_rules = [
   "+cc/surfaces/surface_id_allocator.h",
   "+cc/surfaces/surface_info.h",
   "+cc/surfaces/surface_manager.h",
+  "+cc/surfaces/surface_reference_factory.h",
   "+gpu/command_buffer/client/gpu_memory_buffer_manager.h",
   "+gpu/ipc/client/gpu_channel_host.h",
   "+mojo/public/cpp/system/buffer.h",

ui/aura/mus/client_surface_embedder.cc

+// Copyright 2017 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/aura/mus/client_surface_embedder.h"
+
+#include "cc/surfaces/surface_reference_factory.h"
+#include "ui/aura/mus/surface_id_handler.h"
+#include "ui/aura/window.h"
+
+namespace aura {
+namespace {
+
+// TODO(mfomitchev, samans): Remove these stub classes once the SurfaceReference
+// work is complete.
+class StubSurfaceReference : public cc::SurfaceReferenceBase {
+ public:
+  StubSurfaceReference(scoped_refptr<const cc::SurfaceReferenceFactory> factory)
+      : cc::SurfaceReferenceBase(factory) {}
+
+  ~StubSurfaceReference() override { Destroy(); }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(StubSurfaceReference);
+};
+
+class StubSurfaceReferenceFactory : public cc::SurfaceReferenceFactory {
+ public:
+  StubSurfaceReferenceFactory() = default;
+
+  // cc::SurfaceReferenceFactory:
+  std::unique_ptr<cc::SurfaceReferenceBase> CreateReference(
+      cc::SurfaceReferenceOwner* owner,
+      const cc::SurfaceId& surface_id) const override {
+    return base::MakeUnique<StubSurfaceReference>(make_scoped_refptr(this));
+  }
+
+ protected:
+  ~StubSurfaceReferenceFactory() override = default;
+
+ private:
+  // cc::SurfaceReferenceFactory:
+  void DestroyReference(cc::SurfaceReferenceBase* surface_ref) const override {}
+
+  DISALLOW_COPY_AND_ASSIGN(StubSurfaceReferenceFactory);
+};
+}  // namespace
+
+ClientSurfaceEmbedder::ClientSurfaceEmbedder(Window* window) : window_(window) {
+  surface_layer_ = base::MakeUnique<ui::Layer>(ui::LAYER_TEXTURED);
+  surface_layer_->SetVisible(true);
+  // The frame provided by the parent window->layer() needs to show through
+  // the surface layer.
+  surface_layer_->SetFillsBoundsOpaquely(false);
+
+  clip_layer_ = base::MakeUnique<ui::Layer>(ui::LAYER_NOT_DRAWN);
+  clip_layer_->SetFillsBoundsOpaquely(false);
+
+  clip_layer_->Add(surface_layer_.get());
+  window_->layer()->Add(clip_layer_.get());
+
+  // Window's layer may contain content from this client (the embedder), e.g.
+  // this is the case with window decorations provided by Window Manager.
+  // This content should appear underneath the content of the embedded client.
+  window_->layer()->StackAtTop(clip_layer_.get());
+
+  // We can't set this on window's layer, because that would clip the window
+  // shadow.
+  clip_layer_->SetMasksToBounds(true);
+}
+
+ClientSurfaceEmbedder::~ClientSurfaceEmbedder() = default;
+
+void ClientSurfaceEmbedder::UpdateSurface(const cc::SurfaceInfo& surface_info) {
+  // TODO(mfomitchev): Currently the frame size may not match the window size.
+  // In the future the surface id will be created by Ash (and used with the
+  // surface layer) when the window resize happens, which will ensure that the
+  // surface size matches the window size (unless a timeout occurs).
+  gfx::Size frame_size = surface_info.size_in_pixels();
+  surface_layer_->SetBounds(
+      gfx::Rect(0, 0, frame_size.width(), frame_size.height()));
+  // Clip to window bounds.
+  clip_layer_->SetBounds(
+      gfx::Rect(0, 0, window_->bounds().width(), window_->bounds().height()));
+
+  surface_layer_->SetShowSurface(
+      surface_info, make_scoped_refptr(new StubSurfaceReferenceFactory));
+}
+
+}  // namespace aura

ui/aura/mus/client_surface_embedder.h

+// Copyright 2017 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 <memory>
+
+#include "base/macros.h"
+
+namespace cc {
+class SurfaceInfo;
+}
+
+namespace ui {
+class Layer;
+}
+
+namespace aura {
+
+class Window;
+
+// Used by WindowPortMus when it is embedding a client. Responsible for setting
+// up layers containing content from the client, parenting them to the window's
+// layer, and updating them when the client submits new surfaces.
+class ClientSurfaceEmbedder {
+ public:
+  explicit ClientSurfaceEmbedder(Window* window);
+  ~ClientSurfaceEmbedder();
+
+  // Updates the surface layer and the clip layer based on the surface info.
+  void UpdateSurface(const cc::SurfaceInfo& surface_info);
+
+ private:
+  // The window which embeds the client.
+  Window* window_;
+
+  // Contains the client's content.
+  std::unique_ptr<ui::Layer> surface_layer_;
+
+  // Used for clipping the surface layer to the window bounds.
+  std::unique_ptr<ui::Layer> clip_layer_;
+
+  DISALLOW_COPY_AND_ASSIGN(ClientSurfaceEmbedder);
+};
+
+}  // namespace aura

ui/aura/mus/window_port_mus.cc

@@ -7,6 +7,7 @@
 #include "base/memory/ptr_util.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/transient_window_client.h"
+#include "ui/aura/mus/client_surface_embedder.h"
 #include "ui/aura/mus/property_converter.h"
 #include "ui/aura/mus/surface_id_handler.h"
 #include "ui/aura/mus/window_tree_client.h"
@@ -255,10 +256,22 @@ void WindowPortMus::SetSurfaceInfoFromServer(
     }
   }
   WindowPortMus* parent = Get(window_->parent());
+  // TODO(mfomitchev): This is unused. We probably don't need this.
   if (parent && parent->surface_id_handler_) {
     parent->surface_id_handler_->OnChildWindowSurfaceChanged(window_,
                                                              surface_info);
   }
+
+  // The fact that SetSurfaceIdFromServer was called means that this window
+  // corresponds to an embedded client.
+  if (!client_surface_embedder && surface_info.id().is_valid())
+    client_surface_embedder = base::MakeUnique<ClientSurfaceEmbedder>(window_);
+
+  if (surface_info.id().is_valid())
+    client_surface_embedder->UpdateSurface(surface_info);
+  else
+    client_surface_embedder.reset();
+
   surface_info_ = surface_info;
 }
 

ui/aura/mus/window_port_mus.h

@@ -26,6 +26,7 @@
 
 namespace aura {
 
+class ClientSurfaceEmbedder;
 class PropertyConverter;
 class SurfaceIdHandler;
 class Window;
@@ -243,6 +244,9 @@ class AURA_EXPORT WindowPortMus : public WindowPort, public WindowMus {
 
   Window* window_ = nullptr;
 
+  // Used when this window is embedding a client.
+  std::unique_ptr<ClientSurfaceEmbedder> client_surface_embedder;
+
   ServerChangeIdType next_server_change_id_ = 0;
   ServerChanges server_changes_;