TestInterfaces: support delegate clearing.

content/shell/test_runner/test_interfaces.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 "content/shell/test_runner/test_interfaces.h"
 
 #include <stddef.h>
 
 #include <string>
 
@@ skipping 33 matching lines @@
   test_runner_->SetDelegate(nullptr);
 }
 
 void TestInterfaces::SetMainView(blink::WebView* web_view) {
   // gamepad_controller_ doesn't depend on WebView.
   main_view_ = web_view;
   test_runner_->SetMainView(web_view);
 }
 
 void TestInterfaces::SetDelegate(WebTestDelegate* delegate) {
-  gamepad_controller_ = GamepadController::Create(delegate);
+  if (delegate)
+    gamepad_controller_ = GamepadController::Create(delegate);
+  else
+    gamepad_controller_ = nullptr;
   test_runner_->SetDelegate(delegate);
   delegate_ = delegate;
 }
 
 void TestInterfaces::BindTo(blink::WebFrame* frame) {
   if (gamepad_controller_)
     gamepad_controller_->Install(frame);
   GCController::Install(frame);
 }
 
@@ skipping 87 matching lines @@
 
 blink::WebThemeEngine* TestInterfaces::GetThemeEngine() {
   if (!test_runner_->UseMockTheme())
     return 0;
   if (!theme_engine_.get())
     theme_engine_.reset(new MockWebThemeEngine());
   return theme_engine_.get();
 }
 
 }  // namespace test_runner