Add a command line flag to disable infobars.

chrome/browser/external_tab_container.h

Index: chrome/browser/external_tab_container.h
===================================================================
--- chrome/browser/external_tab_container.h	(revision 42751)
+++ chrome/browser/external_tab_container.h	(working copy)
@@ -65,7 +65,8 @@
             bool handle_top_level_requests,
             TabContents* existing_tab_contents,
             const GURL& initial_url,
-            const GURL& referrer);
+            const GURL& referrer,
+            bool infobars_enabled);
 
   // Unhook the keystroke listener and notify about the closing TabContents.
   // This function gets called from three places, which is fine.
@@ -202,6 +203,8 @@
 
   virtual void TabContentsCreated(TabContents* new_contents);
 
+  virtual bool infobars_enabled();
+
  protected:
   // Overridden from views::WidgetWin:
   virtual LRESULT OnCreate(LPCREATESTRUCT create_struct);
@@ -325,6 +328,9 @@
   // from the host.
   bool pending_;
 
+  // Set to true if the ExternalTabContainer if infobars should be enabled.
+  bool infobars_enabled_;
+
   DISALLOW_COPY_AND_ASSIGN(ExternalTabContainer);
 };