[Extensions] Make extension message bubble factory platform-abstract

chrome/browser/ui/toolbar/toolbar_actions_bar.h

Index: chrome/browser/ui/toolbar/toolbar_actions_bar.h
diff --git a/chrome/browser/ui/toolbar/toolbar_actions_bar.h b/chrome/browser/ui/toolbar/toolbar_actions_bar.h
index 3a6798fc29a10a08f7d57583cb485b201263c7ec..5733d5e4271c84dcbf3c28aec577b033a6c200ac 100644
--- a/chrome/browser/ui/toolbar/toolbar_actions_bar.h
+++ b/chrome/browser/ui/toolbar/toolbar_actions_bar.h
@@ -198,6 +198,9 @@ class ToolbarActionsBar : public extensions::ExtensionToolbarModel::Observer,
   // Sets |overflowed_action_wants_to_run_| to the proper value.
   void SetOverflowedActionWantsToRun();
 
+  // Shows an extension message bubble, if any should be shown.
+  void MaybeShowExtensionBubble();
+
   bool in_overflow_mode() const { return main_bar_ != nullptr; }
 
   // The delegate for this object (in a real build, this is the view).
@@ -247,6 +250,10 @@ class ToolbarActionsBar : public extensions::ExtensionToolbarModel::Observer,
   // True if an action in the overflow menu wants to run.
   bool overflowed_action_wants_to_run_;
 
+  // True if we have checked to see if there is an extension bubble to display,
+  // and done so if one exists.

[Finnur, 2015/04/10 11:24:21]

nit: This comment is very confusing. Especially the "and done so" part. :)
Can you reword it?

[Devlin, 2015/04/10 15:55:20]

Done.

+  bool checked_extension_bubble_;
+
   DISALLOW_COPY_AND_ASSIGN(ToolbarActionsBar);
 };