Fix Flash fullscreen focus regressions, and add interactive_ui_tests.

content/browser/web_contents/web_contents_view_aura.cc

Index: content/browser/web_contents/web_contents_view_aura.cc
diff --git a/content/browser/web_contents/web_contents_view_aura.cc b/content/browser/web_contents/web_contents_view_aura.cc
index 3ba80e72ff818489f835cd3ef50174083b910ab2..3a9e7abef6deb7fcc81da206248f59d612280071 100644
--- a/content/browser/web_contents/web_contents_view_aura.cc
+++ b/content/browser/web_contents/web_contents_view_aura.cc
@@ -1033,7 +1033,10 @@ void WebContentsViewAura::Focus() {
   if (delegate_.get() && delegate_->Focus())
     return;
 
-  RenderWidgetHostView* rwhv = web_contents_->GetRenderWidgetHostView();
+  RenderWidgetHostView* rwhv =
+      web_contents_->GetFullscreenRenderWidgetHostView();
+  if (!rwhv)
+    rwhv = web_contents_->GetRenderWidgetHostView();
   if (rwhv)
     rwhv->Focus();
 }