Change CaptureSynchronizer and PointerWatcherEventRouter to support multiple CaptureClients.

ui/aura/client/capture_client.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_AURA_CLIENT_CAPTURE_CLIENT_H_
 #define UI_AURA_CLIENT_CAPTURE_CLIENT_H_
 
 #include "ui/aura/aura_export.h"
+#include "ui/aura/window.h"
 
 namespace aura {
 class Window;
 
 namespace client {
 
 class CaptureClientObserver;
 
 // An interface implemented by an object that manages input capture.
 class AURA_EXPORT CaptureClient {
@@ skipping 23 matching lines @@
 
 // Sets/Gets the capture client on the root Window.
 AURA_EXPORT void SetCaptureClient(Window* root_window,
                                   CaptureClient* client);
 AURA_EXPORT CaptureClient* GetCaptureClient(Window* root_window);
 
 // A utility function to get the current capture window. Returns NULL
 // if the window doesn't have a root window, or there is no capture window.
 AURA_EXPORT Window* GetCaptureWindow(Window* window);
 
+// The capture client is stored on the window using this property.
+AURA_EXPORT extern const WindowProperty<CaptureClient*>* const
+    kRootWindowCaptureClientKey;

[sadrul, 2017/01/21 03:23:37]

Can you move this into aura_constants.h? since the other exported properties are
also in there.

[riajiang, 2017/01/24 19:36:21]

The key is not needed anymore so deleted here.

+
 }  // namespace client
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_CAPTURE_CLIENT_H_