Fix Flash fullscreen focus regressions, and add interactive_ui_tests.

content/browser/renderer_host/render_widget_host_delegate.h

Index: content/browser/renderer_host/render_widget_host_delegate.h
diff --git a/content/browser/renderer_host/render_widget_host_delegate.h b/content/browser/renderer_host/render_widget_host_delegate.h
index d3bd78dba060a6ed4adb72b8fd3e716287d27499..669dc255ba462a6bec3d35b62364a65bcc7dc008 100644
--- a/content/browser/renderer_host/render_widget_host_delegate.h
+++ b/content/browser/renderer_host/render_widget_host_delegate.h
@@ -31,6 +31,9 @@ class CONTENT_EXPORT RenderWidgetHostDelegate {
   // The RenderWidgetHost is going to be deleted.
   virtual void RenderWidgetDeleted(RenderWidgetHostImpl* render_widget_host) {}
 
+  // The RenderWidgetHost got the focus.
+  virtual void RenderWidgetGotFocus(RenderWidgetHostImpl* render_widget_host) {}
+
   // Callback to give the browser a chance to handle the specified keyboard
   // event before sending it to the renderer.
   // Returns true if the |event| was handled. Otherwise, if the |event| would