Implement temporary reference assignment with DisplayCompositor.

services/ui/ws/window_server.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_server.h"
 
 #include <set>
 #include <string>
 
 #include "base/logging.h"
@@ skipping 588 matching lines @@
   event_dispatcher->UpdateNonClientAreaForCurrentWindow();
   display_root->display()->UpdateNativeCursor(
       event_dispatcher->GetCurrentMouseCursor());
 }
 
 bool WindowServer::IsUserInHighContrastMode(const UserId& user) const {
   const auto iter = high_contrast_mode_.find(user);
   return (iter == high_contrast_mode_.end()) ? false : iter->second;
 }
 
+ServerWindow* WindowServer::FindCompositorFrameSinkParent(

[Fady Samuel, 2017/02/24 18:07:38]

nit: TODO that we should plumb a bool to ServerWindow to indicate that they will
create CompositorFrames / CompositorFrameSinks.

[kylechar, 2017/02/28 18:07:17]

Done.

+    ServerWindow* window) {
+  DCHECK(window->parent());
+
+  WindowTree* window_tree = GetTreeWithId(window->parent()->id().client_id);
+  if (window_tree) {
+    // If the parent of |window| is part of a WindowTree, the WindowTree root
+    // that contains |window| should be backed by a CompositorFrameSink.
+    for (const ServerWindow* root : window_tree->roots()) {
+      if (root->Contains(window))
+        // TODO(kylechar): There must be a better way to do this.
+        return const_cast<ServerWindow*>(root);
+    }
+  }
+
+  // The parent of |window| might be a display root which isn't part of a
+  // WindowTree. Display roots will always be backed by a CompositorFrameSink.
+  Display* display = display_manager_->GetDisplayContaining(window);
+  if (display && display->root_window() == window->parent())
+    return display->root_window();
+
+  return nullptr;
+}
+
 ServerWindow* WindowServer::GetRootWindow(const ServerWindow* window) {
   Display* display = display_manager_->GetDisplayContaining(window);
   return display ? display->root_window() : nullptr;
 }
 
 void WindowServer::OnWindowDestroyed(ServerWindow* window) {
   ProcessWindowDeleted(window);
 }
 
 void WindowServer::OnWillChangeWindowHierarchy(ServerWindow* window,
@@ skipping 135 matching lines @@
   // If we're deleting a window, then this is a superfluous message.
   if (current_operation_type() == OperationType::DELETE_WINDOW)
     return;
   for (auto& pair : tree_map_) {
     pair.second->ProcessTransientWindowRemoved(window, transient_child,
                                                IsOperationSource(pair.first));
   }
 }
 
 void WindowServer::OnGpuServiceInitialized() {
-  // TODO(kylechar): When gpu channel is removed, this can instead happen
-  // earlier, after GpuHost::OnInitialized().
   delegate_->StartDisplayInit();
 }
 
 void WindowServer::OnSurfaceCreated(const cc::SurfaceInfo& surface_info) {
   WindowId window_id(
       WindowIdFromTransportId(surface_info.id().frame_sink_id().client_id()));
   ServerWindow* window = GetWindow(window_id);
   // If the window doesn't have a parent then we have nothing to propagate.
-  if (!window)
+  if (!window) {
+    display_compositor_->DropTemporaryReference(surface_info.id());
     return;
+  }
 
   // FrameGenerator will add an appropriate reference for the new surface.
   DCHECK(display_manager_->GetDisplayContaining(window));
   auto* display = display_manager_->GetDisplayContaining(window);
   if (window == display->GetActiveRootWindow()) {
     display->platform_display()->GetFrameGenerator()->OnSurfaceCreated(
         surface_info);
   }
 
   // This is only used for testing to observe that a window has a
   // CompositorFrame.
   if (!window_paint_callback_.is_null())
     window_paint_callback_.Run(window);
 
-  if (!window->parent())
+  if (!window->parent()) {
+    // If |window| is a display root then a surface reference has already been
+    // added by the DisplayCompositor.
+    display_compositor_->DropTemporaryReference(surface_info.id());
     return;
+  }
 
   WindowTree* window_tree = GetTreeWithId(window->parent()->id().client_id);
   if (window_tree)
     window_tree->ProcessWindowSurfaceChanged(window, surface_info);
+
+  ServerWindow* parent = FindCompositorFrameSinkParent(window);

[Fady Samuel, 2017/02/24 18:07:38]

nit: compositing_parent

[kylechar, 2017/02/28 18:07:16]

Done.

+  if (parent) {
+    auto* frame_sink_manager = parent->GetOrCreateCompositorFrameSinkManager();
+    frame_sink_manager->ClaimTemporaryReference(surface_info.id());

[Fady Samuel, 2017/02/24 18:07:38]

Add a comment here about what this is doing.

[kylechar, 2017/02/28 18:07:15]

Done.

+  } else {
+    display_compositor_->DropTemporaryReference(surface_info.id());
+  }
 }
 
 void WindowServer::OnActiveUserIdChanged(const UserId& previously_active_id,
                                          const UserId& active_id) {
 }
 
 void WindowServer::OnUserIdAdded(const UserId& id) {
   activity_monitor_map_[id] = base::MakeUnique<UserActivityMonitor>(nullptr);
 }
 
 void WindowServer::OnUserIdRemoved(const UserId& id) {
   activity_monitor_map_.erase(id);
 }
 
 }  // namespace ws
 }  // namespace ui