[Web Intents] Display throbber when loading inline disposition.

chrome/browser/ui/intents/web_intent_picker.h

Index: chrome/browser/ui/intents/web_intent_picker.h
diff --git a/chrome/browser/ui/intents/web_intent_picker.h b/chrome/browser/ui/intents/web_intent_picker.h
index 31f5547725626cded21cbdb86f406665273b690c..c9f81bea594fa8ed8f2e49ba05ab4629c38d9bb8 100644
--- a/chrome/browser/ui/intents/web_intent_picker.h
+++ b/chrome/browser/ui/intents/web_intent_picker.h
@@ -49,6 +49,10 @@ class WebIntentPicker {
   // activities.
   virtual void OnPendingAsyncCompleted() {}
 
+  // Called when the inline disposition's web contents have been loaded.
+  virtual void OnInlineDispositionWebContentsLoaded(
+      content::WebContents* web_contents) {}
+
   // Get the default size of the inline disposition tab container.
   static gfx::Size GetDefaultInlineDispositionSize(
       content::WebContents* web_contents);