Disable overscroll navigation when emulating touch.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 2687a7845a87682f0b2b29688c0f27ff524a3cc0..e111365bc9842a439daa83d09949786f97367048 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -506,6 +506,7 @@ class CONTENT_EXPORT WebContentsImpl
   virtual bool HandleGestureEvent(
       const blink::WebGestureEvent& event) OVERRIDE;
   virtual void DidSendScreenRects(RenderWidgetHostImpl* rwh) OVERRIDE;
+  virtual void SetOverscrollContentDisabled(bool disabled) OVERRIDE;
 #if defined(OS_WIN)
   virtual gfx::NativeViewAccessible GetParentNativeViewAccessible() OVERRIDE;
 #endif
@@ -1122,6 +1123,9 @@ class CONTENT_EXPORT WebContentsImpl
   // different process from its parent page.
   bool is_subframe_;
 
+  // Whether overscrolling content is explicitly disabled.
+  bool overscroll_content_disabled_;
+
   // Whether the last JavaScript dialog shown was suppressed. Used for testing.
   bool last_dialog_suppressed_;