Pass result of blockage across content API when new tab blocked.

chrome/browser/ui/webui/chrome_web_contents_handler.cc

Index: chrome/browser/ui/webui/chrome_web_contents_handler.cc
===================================================================
--- chrome/browser/ui/webui/chrome_web_contents_handler.cc	(revision 154307)
+++ chrome/browser/ui/webui/chrome_web_contents_handler.cc	(working copy)
@@ -66,8 +66,8 @@
 // operation originated. |disposition| controls how the new tab should be
 // opened. |initial_pos| is the position of the window if a new window is
 // created.  |user_gesture| is true if the operation was started by a user
-// gesture.
-void ChromeWebContentsHandler::AddNewContents(
+// gesture. Returns false if the tab was blocked.
+bool ChromeWebContentsHandler::AddNewContents(
     content::BrowserContext* context,
     WebContents* source,
     WebContents* new_contents,
@@ -75,7 +75,7 @@
     const gfx::Rect& initial_pos,
     bool user_gesture) {
   if (!context)
-    return;
+    return false;
 
   Profile* profile = Profile::FromBrowserContext(context);
   Browser* browser = browser::FindTabbedBrowser(profile, false);
@@ -96,4 +96,6 @@
   // Close the browser if chrome::Navigate created a new one.
   if (browser_created && (browser != params.browser))
     browser->window()->Close();
+
+  return true;
 }