Adding a way to associate Android Activities with PlatformWindowAndroid

ui/aura/client/aura_constants.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_AURA_CONSTANTS_H_
 #define UI_AURA_CLIENT_AURA_CONSTANTS_H_
 
 #include "ui/aura/aura_export.h"
 #include "ui/aura/window.h"
 #include "ui/base/ui_base_types.h"
 
+#if defined(OS_ANDROID)
+#include "base/android/jni_android.h"
+#endif
+
 namespace ui {
 class InputMethod;
 }
 
 namespace aura {
 namespace client {
 
 // Alphabetical sort.
 
+#if defined(OS_ANDROID)
+// A property key to store Android Activity associated with the root window.
+AURA_EXPORT extern const WindowProperty<jobject>* const kActivityForRootWindow;

[mfomitchev, 2015/11/19 20:57:05]

Not sure if this is an appropriate place, but we'd need to use
kActivityForRootWindow from multiple places, so it can't be simply defined in
window_tree_host_android.cc for example.

+#endif
+
 // A property key to store always-on-top flag.
 AURA_EXPORT extern const WindowProperty<bool>* const kAlwaysOnTopKey;
 
 // A property key to store whether animations are disabled for the window. Type
 // of value is an int.
 AURA_EXPORT extern const WindowProperty<bool>* const kAnimationsDisabledKey;
 
 // A property key to store the can-maximize flag.
 AURA_EXPORT extern const WindowProperty<bool>* const kCanMaximizeKey;
 
@@ skipping 29 matching lines @@
 // See ui/base/ui_base_types.h for its definition.
 AURA_EXPORT extern const WindowProperty<ui::WindowShowState>* const
     kShowStateKey;
 
 // Alphabetical sort.
 
 }  // namespace client
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_AURA_CONSTANTS_H_