Disable delegation to picker controller once it is deleted.

chrome/browser/ui/intents/web_intent_picker_controller_browsertest.cc

 // Copyright (c) 2012 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 <algorithm>
 #include <iterator>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
@@ skipping 111 matching lines @@
   virtual void Close() OVERRIDE { StopWaiting(); }
   virtual void SetActionString(const string16& action) OVERRIDE {}
   virtual void OnExtensionInstallSuccess(const std::string& id) OVERRIDE {
     num_extensions_installed_++;
   }
   virtual void OnExtensionInstallFailure(const std::string& id) OVERRIDE {}
   virtual void OnInlineDispositionAutoResize(const gfx::Size& size) OVERRIDE {}
   virtual void OnPendingAsyncCompleted() OVERRIDE {
     StopWaiting();
   }
+  virtual void InvalidateDelegate() OVERRIDE {
+    delegate_ = NULL;
+  }
 
   // WebIntentPickerModelObserver implementation.
   virtual void OnModelChanged(WebIntentPickerModel* model) OVERRIDE {
     num_installed_services_ =
         static_cast<int>(model->GetInstalledServiceCount());
   }
   virtual void OnFaviconChanged(
       WebIntentPickerModel* model, size_t index) OVERRIDE {
     num_icons_changed_++;
   }
@@ skipping 609 matching lines @@
                  service_web_contents));
   observer.Wait();
   picker_.Wait();
 
   // The service tab is closed and the picker is shown again
   // on the original tab.
   EXPECT_EQ(1, browser()->tab_count());
   EXPECT_EQ(2, picker_.num_installed_services_);
   EXPECT_EQ(0, picker_.num_inline_disposition_);
 }