UI resource are evicted when LTH is set to not visible.

cc/trees/layer_tree_host_impl.h

 // Copyright 2011 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 CC_TREES_LAYER_TREE_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <list>
 #include <string>
 #include <vector>
@@ skipping 365 matching lines @@
   scoped_ptr<base::Value> AsValueWithFrame(FrameData* frame) const;
   scoped_ptr<base::Value> ActivationStateAsValue() const;
 
   bool page_scale_animation_active() const { return !!page_scale_animation_; }
 
   void CreateUIResource(UIResourceId uid,
                         scoped_refptr<UIResourceBitmap> bitmap);
   // Deletes a UI resource.  May safely be called more than once.
   void DeleteUIResource(UIResourceId uid);
 
+  // Release all the UI resources.
+  void ReleaseUIResources();
+
   ResourceProvider::ResourceId ResourceIdForUIResource(UIResourceId uid) const;
 
  protected:
   LayerTreeHostImpl(
       const LayerTreeSettings& settings,
       LayerTreeHostImplClient* client,
       Proxy* proxy,
       RenderingStatsInstrumentation* rendering_stats_instrumentation);
   virtual void ActivatePendingTree();
 
@@ skipping 161 matching lines @@
 
   // Optional callback to notify of new tree activations.
   base::Closure tree_activation_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_