Split content script injections into multiple tasks

content/public/renderer/content_renderer_client.h

Index: content/public/renderer/content_renderer_client.h
diff --git a/content/public/renderer/content_renderer_client.h b/content/public/renderer/content_renderer_client.h
index 0764782e713aef8cdfad818e125e5f9222553b6f..78543f883ce061fd47b90459db6f184551651c57 100644
--- a/content/public/renderer/content_renderer_client.h
+++ b/content/public/renderer/content_renderer_client.h
@@ -319,6 +319,10 @@ class CONTENT_EXPORT ContentRendererClient {
   // This method may invalidate the frame.
   virtual void RunScriptsAtDocumentEnd(RenderFrame* render_frame) {}
 
+  // Notifies that the window.onload event is about to fire.
+  // This method may invalidate the frame.
+  virtual void RunScriptsAtDocumentIdle(RenderFrame* render_frame) {}
+
   // Allows subclasses to enable some runtime features before Blink has
   // started.
   virtual void SetRuntimeFeaturesDefaultsBeforeBlinkInitialization() {}