Disable overscroll navigation when emulating touch.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 1df288a3b8809c23c804c7260e833cecb33d8b94..6656462cdacded576ac97870b1ab87c6f1ea4c60 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -347,6 +347,7 @@ WebContentsImpl::WebContentsImpl(
       render_view_message_source_(NULL),
       fullscreen_widget_routing_id_(MSG_ROUTING_NONE),
       is_subframe_(false),
+      touch_emulation_enabled_(false),
       last_dialog_suppressed_(false) {
   for (size_t i = 0; i < g_created_callbacks.Get().size(); i++)
     g_created_callbacks.Get().at(i).Run(this);
@@ -613,7 +614,7 @@ void WebContentsImpl::SetDelegate(WebContentsDelegate* delegate) {
     delegate_->Attach(this);
     // Ensure the visible RVH reflects the new delegate's preferences.
     if (view_)
-      view_->SetOverscrollControllerEnabled(delegate->CanOverscrollContent());
+      view_->SetOverscrollControllerEnabled(CanOverscrollContent());
   }
 }
 
@@ -1698,6 +1699,12 @@ void WebContentsImpl::DidSendScreenRects(RenderWidgetHostImpl* rwh) {
     browser_plugin_embedder_->DidSendScreenRects();
 }
 
+void WebContentsImpl::OnTouchEmulationEnabled(bool enabled) {
+  touch_emulation_enabled_ = enabled;
+  if (view_)
+    view_->SetOverscrollControllerEnabled(CanOverscrollContent());
+}
+
 void WebContentsImpl::UpdatePreferredSize(const gfx::Size& pref_size) {
   const gfx::Size old_size = GetPreferredSize();
   preferred_size_ = pref_size;
@@ -2456,10 +2463,9 @@ void WebContentsImpl::DidNavigateMainFramePostCommit(
   FOR_EACH_OBSERVER(WebContentsObserver, observers_,
                     DidNavigateMainFrame(details, params));
 
-  if (delegate_) {
+  if (delegate_)
     delegate_->DidNavigateMainFramePostCommit(this);
-    view_->SetOverscrollControllerEnabled(delegate_->CanOverscrollContent());
-  }
+  view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 }
 
 void WebContentsImpl::DidNavigateAnyFramePostCommit(
@@ -2484,6 +2490,10 @@ void WebContentsImpl::SetMainFrameMimeType(const std::string& mime_type) {
 }
 
 bool WebContentsImpl::CanOverscrollContent() const {
+  // Disable overscroll when touch emulation is on. See crbug.com/369938.
+  if (touch_emulation_enabled_)
+    return false;
+
   if (delegate_)
     return delegate_->CanOverscrollContent();
 
@@ -3295,7 +3305,7 @@ void WebContentsImpl::RenderViewCreated(RenderViewHost* render_view_host) {
     return;
 
   if (delegate_)
-    view_->SetOverscrollControllerEnabled(delegate_->CanOverscrollContent());
+    view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 
   NotificationService::current()->Notify(
       NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED,
@@ -3797,7 +3807,7 @@ void WebContentsImpl::NotifySwappedFromRenderManager(RenderViewHost* old_host,
 
   // Make sure the visible RVH reflects the new delegate's preferences.
   if (delegate_)
-    view_->SetOverscrollControllerEnabled(delegate_->CanOverscrollContent());
+    view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 
   view_->RenderViewSwappedIn(new_host);
 }