Add an extension override bubble and warning box for proxy extensions.

chrome/browser/extensions/extension_message_bubble_controller.h

Index: chrome/browser/extensions/extension_message_bubble_controller.h
diff --git a/chrome/browser/extensions/extension_message_bubble_controller.h b/chrome/browser/extensions/extension_message_bubble_controller.h
index e2a64fd82575e83639a9cdc159c91c447557b186..e3f522dce54cdb7a9fd66386a171a522d84f5e5c 100644
--- a/chrome/browser/extensions/extension_message_bubble_controller.h
+++ b/chrome/browser/extensions/extension_message_bubble_controller.h
@@ -42,7 +42,13 @@ class ExtensionMessageBubbleController {
 
     // Text for various UI labels shown in the bubble.
     virtual base::string16 GetTitle() const = 0;
-    virtual base::string16 GetMessageBody() const = 0;
+    // Fetches the message to show in the body. |anchored_to_browser_action|
+    // will be true if the bubble is anchored against a specific extension
+    // icon, allowing the bubble to show a different message than when it is
+    // anchored against something else (e.g. show "This extension has..."
+    // instead of "An extension has...").
+    virtual base::string16 GetMessageBody(
+        bool anchored_to_browser_action) const = 0;
     virtual base::string16 GetOverflowText(
         const base::string16& overflow_count) const = 0;
     virtual base::string16 GetLearnMoreLabel() const = 0;