[Android WebView] OnMemoryPressure to drop tile memory

android_webview/browser/in_process_view_renderer.h

Index: android_webview/browser/in_process_view_renderer.h
diff --git a/android_webview/browser/in_process_view_renderer.h b/android_webview/browser/in_process_view_renderer.h
index ce5c5841f6ad1d04249c4e10bfbf760abc4d875d..dfe864ab5f89fcc39ed83906a03f4f3bdb942329 100644
--- a/android_webview/browser/in_process_view_renderer.h
+++ b/android_webview/browser/in_process_view_renderer.h
@@ -71,6 +71,7 @@ class InProcessViewRenderer : public BrowserViewRenderer,
   virtual bool IsAttachedToWindow() OVERRIDE;
   virtual bool IsVisible() OVERRIDE;
   virtual gfx::Rect GetScreenRect() OVERRIDE;
+  virtual void TrimMemory(int level) OVERRIDE;
 
   // SynchronousCompositorClient overrides
   virtual void DidInitializeCompositor(
@@ -108,6 +109,7 @@ class InProcessViewRenderer : public BrowserViewRenderer,
   // If we call up view invalidate and OnDraw is not called before a deadline,
   // then we keep ticking the SynchronousCompositor so it can make progress.
   void FallbackTickFired();
+  void ForceCompositeSW();
 
   void NoLongerExpectsDrawGL();