Bug 1301514 - Destroy browser API frame scripts during swap. r=kanru

When swapping content from <iframe mozbrowser> to <xul:browser>, we now stop the
frame scripts that implement the content side of the browser API since they are
no longer needed and can cause issues if they remain active.

MozReview-Commit-ID: JrecxA4MI93

dom/html/nsGenericHTMLFrameElement.cpp

@@ -726,3 +726,11 @@ nsGenericHTMLFrameElement::InitializeBrowserAPI()
   InitBrowserElementAPI();
   return NS_OK;
 }
+
+NS_IMETHODIMP
+nsGenericHTMLFrameElement::DestroyBrowserFrameScripts()
+{
+  MOZ_ASSERT(mFrameLoader);
+  DestroyBrowserElementFrameScripts();
+  return NS_OK;
+}