mojo: Make InterfacePtr<> testable in if() statements without .get().

mojo/services/html_viewer/html_viewer.cc

 // 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.
 
 #include "base/message_loop/message_loop.h"
 #include "mojo/public/cpp/application/application_connection.h"
 #include "mojo/public/cpp/application/application_delegate.h"
 #include "mojo/public/cpp/application/application_impl.h"
 #include "mojo/services/html_viewer/blink_platform_impl.h"
 #include "mojo/services/html_viewer/html_document_view.h"
@@ skipping 65 matching lines @@
             GetServiceProvider(), view_manager);
     document_view_->AttachToNode(root);
     MaybeLoad();
   }
   virtual void OnViewManagerDisconnected(
       view_manager::ViewManager* view_manager) OVERRIDE {
     base::MessageLoop::current()->Quit();
   }
 
   void MaybeLoad() {
-    if (document_view_ && response_.get())
+    if (document_view_ && response_)
       document_view_->Load(response_.Pass());
   }
 
   scoped_ptr<BlinkPlatformImpl> blink_platform_impl_;
   ApplicationImpl* application_impl_;
 
   // TODO(darin): Figure out proper ownership of this instance.
   HTMLDocumentView* document_view_;
   URLResponsePtr response_;
 
   DISALLOW_COPY_AND_ASSIGN(HTMLViewer);
 };
 
 void NavigatorImpl::Navigate(
     uint32_t node_id,
     navigation::NavigationDetailsPtr navigation_details,
     navigation::ResponseDetailsPtr response_details) {
   viewer_->Load(response_details->response.Pass());
 }
 
 // static
 ApplicationDelegate* ApplicationDelegate::Create() {
   return new HTMLViewer;
 }
 
 }