Make event-targeting asynchronous in window server.

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 51 matching lines @@
 
 WindowServer::WindowServer(WindowServerDelegate* delegate)
     : delegate_(delegate),
       next_client_id_(1),
       display_manager_(new DisplayManager(this, &user_id_tracker_)),
       current_operation_(nullptr),
       in_destructor_(false),
       next_wm_change_id_(0),
       gpu_host_(new GpuHost(this)),
       window_manager_window_tree_factory_set_(this, &user_id_tracker_),
-      frame_sink_manager_client_binding_(this) {
+      frame_sink_manager_client_binding_(this),
+      weak_ptr_factory_(this) {
   user_id_tracker_.AddObserver(this);
   OnUserIdAdded(user_id_tracker_.active_id());
   gpu_host_->CreateFrameSinkManager(
       mojo::MakeRequest(&frame_sink_manager_),
       frame_sink_manager_client_binding_.CreateInterfacePtrAndBind());
 }
 
 WindowServer::~WindowServer() {
   in_destructor_ = true;
 
@@ skipping 508 matching lines @@
   CHECK(current_operation_);
   current_operation_ = nullptr;
 }
 
 void WindowServer::UpdateNativeCursorFromMouseLocation(ServerWindow* window) {
   WindowManagerDisplayRoot* display_root =
       display_manager_->GetWindowManagerDisplayRoot(window);
   if (display_root) {
     EventDispatcher* event_dispatcher =
         display_root->window_manager_state()->event_dispatcher();
-    event_dispatcher->UpdateCursorProviderByLastKnownLocation();
-    display_root->display()->UpdateNativeCursor(
-        event_dispatcher->GetCurrentMouseCursor());
+    event_dispatcher->UpdateCursorProviderByLastKnownLocation(
+        base::Bind(&WindowServer::OnCursorUpdated,
+                   weak_ptr_factory_.GetWeakPtr(), display_root));

[sky, 2017/05/15 21:20:23]

In this code you shouldn't need a weakptrfactory as WindowServer owns everything
and will outlive the eventdispatcher.

[riajiang, 2017/05/17 02:01:59]

Ah I see. And deleted this since not passing a callback anymore.

   }
 }
 
 void WindowServer::UpdateNativeCursorIfOver(ServerWindow* window) {
   WindowManagerDisplayRoot* display_root =
       display_manager_->GetWindowManagerDisplayRoot(window);
   if (!display_root)
     return;
 
   EventDispatcher* event_dispatcher =
       display_root->window_manager_state()->event_dispatcher();
   if (window != event_dispatcher->GetWindowForMouseCursor())
     return;
 
-  event_dispatcher->UpdateNonClientAreaForCurrentWindow();
+  event_dispatcher->UpdateNonClientAreaForCurrentWindow(
+      base::Bind(&WindowServer::OnCursorUpdated, weak_ptr_factory_.GetWeakPtr(),
+                 display_root));
+}
+
+void WindowServer::OnCursorUpdated(WindowManagerDisplayRoot* display_root) {

[sky, 2017/05/15 21:20:24]

Style guide says position of declaration and defintion should match.

   display_root->display()->UpdateNativeCursor(
-      event_dispatcher->GetCurrentMouseCursor());
+      display_root->window_manager_state()
+          ->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;
 }
 
 void WindowServer::HandleTemporaryReferenceForNewSurface(
     const cc::SurfaceId& surface_id,
     ServerWindow* window) {
@@ skipping 240 matching lines @@
 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