Check for delegate in OnMouseEvent

Change-Id: I78ca835371a0cf70e3dcb7630a91838ca40e9005

BUG=107596
TEST=See issue

Review URL: http://codereview.chromium.org/8914017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114513 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/renderer_host/render_widget_host_view_aura.cc

@@ -522,7 +522,8 @@ bool RenderWidgetHostViewAura::OnMouseEvent(aura::MouseEvent* event) {
 
   // Needed to propagate mouse event to native_tab_contents_view_aura.
   // TODO(pkotwicz): Find a better way of doing this.
-  window_->parent()->delegate()->OnMouseEvent(event);
+  if (window_->parent()->delegate())
+    window_->parent()->delegate()->OnMouseEvent(event);
 
   // Return true so that we receive released/drag events.
   return true;