android: Use UIResource for overscroll glow

ui/base/android/system_ui_resource.h

+// 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.
+
+#ifndef UI_BASE_ANDROID_SYSTEM_UI_RESOURCE_H_
+#define UI_BASE_ANDROID_SYSTEM_UI_RESOURCE_H_
+
+#include "cc/resources/ui_resource_client.h"
+#include "ui/base/ui_base_export.h"
+
+namespace ui {
+
+class UI_BASE_EXPORT SystemUIResourceClient {
+ public:
+  virtual void OnUIResourceIdChanged() = 0;
+  virtual ~SystemUIResourceClient() {}
+};
+
+class UI_BASE_EXPORT SystemUIResource {
+ public:
+  enum Type { OVERSCROLL_EDGE, OVERSCROLL_GLOW };
+
+  virtual cc::UIResourceId id() = 0;

[jdduke (slow), 2014/07/12 01:01:09]

Do you anticipate having multiple implementations of this? Otherwise I wonder if
we should just implement it here? 

[powei, 2014/07/16 17:10:52]

Done.  Moved SystemUIResource to content

+  virtual void Load() = 0;
+  virtual void SetClient(SystemUIResourceClient* client) = 0;
+
+  virtual ~SystemUIResource() {}
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_ANDROID_SYSTEM_UI_RESOURCE_H_