Add service registration for Mojo services defined under chrome/

chrome/browser/extensions/chrome_extension_web_contents_observer.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_CHROME_EXTENSION_WEB_CONTENTS_OBSERVER_H_
 #define CHROME_BROWSER_EXTENSIONS_CHROME_EXTENSION_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/compiler_specific.h"
 #include "base/strings/string16.h"
 #include "content/public/browser/web_contents_user_data.h"
@@ skipping 16 matching lines @@
   friend class content::WebContentsUserData<ChromeExtensionWebContentsObserver>;
 
   explicit ChromeExtensionWebContentsObserver(
       content::WebContents* web_contents);
   ~ChromeExtensionWebContentsObserver() override;
 
   // content::WebContentsObserver overrides.
   void RenderViewCreated(content::RenderViewHost* render_view_host) override;
   bool OnMessageReceived(const IPC::Message& message,
                          content::RenderFrameHost* render_frame_host) override;
+  void RegisterMojoServices(content::RenderFrameHost* render_frame_host,

[mark a. foltz, 2015/03/27 20:24:11]

Usually observers don't expose methods to callers that side effect the thing
being observed...

Or maybe this should be OnRegisterMojoServices?

[Kevin M, 2015/03/27 22:42:37]

Moved this out of the WebContentsObserver overrides block, since this is
actually just overriding ExtensionWebContentsObserver's method.

This does indeed change the object being observed, but it's no different than
preexisting functionality. sammc@ might be able to comment on that decision.

I believe it should stay as RegisterMojoServices because the method itself is
what's doing the Mojo registration; it's not fired after the fact.

[Sam McNally, 2015/03/31 23:38:51]

This might be better off as a method in ExtensionsBrowserClient, to be called
from service_registration.cc.

[Kevin M, 2015/04/01 23:23:50]

Done, thanks for the suggestion.

+                            const Extension* extension) override;
 
   // Adds a message to the extensions ErrorConsole.
   void OnDetailedConsoleMessageAdded(const base::string16& message,
                                      const base::string16& source,
                                      const StackTrace& stack_trace,
                                      int32 severity_level);
 
   // Reloads an extension if it is on the terminated list.
   void ReloadIfTerminated(content::RenderViewHost* render_view_host);
 
   DISALLOW_COPY_AND_ASSIGN(ChromeExtensionWebContentsObserver);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_CHROME_EXTENSION_WEB_CONTENTS_OBSERVER_H_