Only send the FrameSinkId to client when it is necessary

services/ui/ws/window_tree.cc

 // Copyright 2014 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 "services/ui/ws/window_tree.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 128 matching lines @@
       display ? display->GetFocusedWindow() : nullptr;
   if (focused_window)
     focused_window = access_policy_->GetWindowForFocusChange(focused_window);
   ClientWindowId focused_window_id;
   if (focused_window)
     IsWindowKnown(focused_window, &focused_window_id);
 
   const bool drawn = root->parent() && root->parent()->IsDrawn();
   client()->OnEmbed(id_, WindowToWindowData(to_send.front()), std::move(tree),
                     display_id, focused_window_id.id, drawn,
-                    root->frame_sink_id(), root->current_local_surface_id());
+                    root->current_local_surface_id());
 }
 
 void WindowTree::ConfigureWindowManager(
     bool automatically_create_display_roots) {
   // ConfigureWindowManager() should be called early on, before anything
   // else. |waiting_for_top_level_window_info_| must be null as if
   // |waiting_for_top_level_window_info_| is non-null it means we're about to
   // create an associated interface, which doesn't work with pause/resume.
   // TODO(sky): DCHECK temporary until 626869 is sorted out.
   DCHECK(!waiting_for_top_level_window_info_);
@@ skipping 70 matching lines @@
   DCHECK_EQ(0u, client_id_to_window_id_map_.count(client_window_id));
   client_id_to_window_id_map_[client_window_id] = root->id();
   window_id_to_client_id_map_[root->id()] = client_window_id;
   roots_.insert(root);
 
   Display* ws_display = GetDisplay(root);
   DCHECK(ws_display);
 
   window_manager_internal_->WmNewDisplayAdded(
       ws_display->GetDisplay(), WindowToWindowData(root),
-      root->parent()->IsDrawn(), root->frame_sink_id(),
-      root->current_local_surface_id());
+      root->parent()->IsDrawn(), root->current_local_surface_id());
 }
 
 void WindowTree::OnWindowDestroyingTreeImpl(WindowTree* tree) {
   if (event_source_wms_ && event_source_wms_->window_tree() == tree)
     event_source_wms_ = nullptr;
 
   // Notify our client if |tree| was embedded in any of our windows.
   for (const auto* tree_root : tree->roots_) {
     const bool owns_tree_root = tree_root->id().client_id == id_;
     if (owns_tree_root) {
@@ skipping 403 matching lines @@
   }
   client_id_to_window_id_map_[waiting_for_top_level_window_info
                                   ->client_window_id] = window->id();
   window_id_to_client_id_map_[window->id()] =
       waiting_for_top_level_window_info->client_window_id;
   roots_.insert(window);
   Display* display = GetDisplay(window);
   int64_t display_id = display ? display->GetId() : display::kInvalidDisplayId;
   const bool drawn = window->parent() && window->parent()->IsDrawn();
   client()->OnTopLevelCreated(client_change_id, WindowToWindowData(window),
-                              display_id, drawn, window->frame_sink_id(),
+                              display_id, drawn,
                               window->current_local_surface_id());
 }
 
 void WindowTree::AddActivationParent(const ClientWindowId& window_id) {
   ServerWindow* window = GetWindowByClientId(window_id);
   if (window) {
     Display* display = GetDisplay(window);
     if (display) {
       display->AddActivationParent(window);
     } else {
@@ skipping 1551 matching lines @@
 
 void WindowTree::SetDisplayRoot(const display::Display& display,
                                 mojom::WmViewportMetricsPtr viewport_metrics,
                                 bool is_primary_display,
                                 Id window_id,
                                 const SetDisplayRootCallback& callback) {
   ServerWindow* display_root =
       ProcessSetDisplayRoot(display, *viewport_metrics, is_primary_display,
                             ClientWindowId(window_id));
   if (!display_root) {
-    callback.Run(base::Optional<cc::FrameSinkId>());
+    callback.Run(false);
     return;
   }
   display_root->parent()->SetVisible(true);
-  callback.Run(display_root->frame_sink_id());
+  callback.Run(true);
 }
 
 void WindowTree::WmResponse(uint32_t change_id, bool response) {
   if (window_server_->in_move_loop() &&
       window_server_->GetCurrentMoveLoopChangeId() == change_id) {
     ServerWindow* window = window_server_->GetCurrentMoveLoopWindow();
 
     if (window->id().client_id != id_) {
       window_server_->WindowManagerSentBogusMessage();
       window = nullptr;
@@ skipping 252 matching lines @@
   client()->OnCompleteDrop(client_window_id.id, event_flags, cursor_offset,
                            effect_bitmask, callback);
 }
 
 void WindowTree::PerformOnDragDropDone() {
   client()->OnDragDropDone();
 }
 
 }  // namespace ws
 }  // namespace ui