Apply artificial memory pressure when backgrounded.

content/renderer/render_thread_impl.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 CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 66 matching lines @@
 class DomStorageDispatcher;
 class GpuChannelHost;
 class IndexedDBDispatcher;
 class InputEventFilter;
 class InputHandlerManager;
 class MediaStreamCenter;
 class MediaStreamDependencyFactory;
 class P2PSocketDispatcher;
 class PeerConnectionTracker;
 class RendererWebKitPlatformSupportImpl;
+class RenderProcessDiscardableMemoryProvider;
 class RenderProcessObserver;
 class VideoCaptureImplManager;
 class WebDatabaseObserverImpl;
 class WebGraphicsContext3DCommandBufferImpl;
 
 // The RenderThreadImpl class represents a background thread where RenderView
 // instances live.  The RenderThread supports an API that is used by its
 // consumer to talk indirectly to the RenderViews and supporting objects.
 // Likewise, it provides an API for the RenderViews to talk back to the main
 // process (i.e., their corresponding WebContentsImpl).
@@ skipping 362 matching lines @@
   scoped_ptr<media::AudioHardwareConfig> audio_hardware_config_;
 
   HistogramCustomizer histogram_customizer_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_