Android: Don't destroy LayerTreeHost when Surface goes away

ui/android/resources/ui_resource_provider.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_ANDROID_RESOURCES_UI_RESOURCE_PROVIDER_H_
 #define UI_ANDROID_RESOURCES_UI_RESOURCE_PROVIDER_H_
 
 #include "base/containers/hash_tables.h"
 #include "cc/resources/ui_resource_client.h"
 #include "ui/android/ui_android_export.h"
 
 namespace cc {
 class LayerTreeHost;
 }
 
 namespace ui {
 
 class UIResourceClientAndroid;
 
+// TODO(sievers): Remove this class.
 class UI_ANDROID_EXPORT UIResourceProvider {
  public:
-  UIResourceProvider();
-  ~UIResourceProvider();
+  UIResourceProvider(cc::LayerTreeHost* host);
+  virtual ~UIResourceProvider();
 
-  void SetLayerTreeHost(cc::LayerTreeHost* host);
-
-  void UIResourcesAreInvalid();
+  void OnUIResourcesEvicted();
 
   virtual cc::UIResourceId CreateUIResource(
       ui::UIResourceClientAndroid* client);
 
   virtual void DeleteUIResource(cc::UIResourceId resource_id);
 
   void SetSupportsETC1NonPowerOfTwo(bool supports_etc1_npot) {
     supports_etc1_npot_ = supports_etc1_npot;
   }
 
   virtual bool SupportsETC1NonPowerOfTwo() const;
 
  private:
   typedef base::hash_map<cc::UIResourceId, ui::UIResourceClientAndroid*>
       UIResourceClientMap;
   UIResourceClientMap ui_resource_client_map_;
   cc::LayerTreeHost* host_;
   bool supports_etc1_npot_;
 
   DISALLOW_COPY_AND_ASSIGN(UIResourceProvider);
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_RESOURCES_UI_RESOURCE_PROVIDER_H_