html_viewer: Make sure window.internals is set-up correctly in layout-tests.

components/html_viewer/web_test_delegate_impl.cc

 // Copyright 2015 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 "components/html_viewer/web_test_delegate_impl.h"
 
 #include "base/time/time.h"
 #include "cc/layers/texture_layer.h"
 #include "components/test_runner/web_task.h"
 #include "components/test_runner/web_test_interfaces.h"
@@ skipping 210 matching lines @@
   NOTIMPLEMENTED();
   return std::string();
 }
 
 void WebTestDelegateImpl::SetLocale(const std::string& locale) {
   NOTIMPLEMENTED();
 }
 
 void WebTestDelegateImpl::TestFinished() {
   test_interfaces_->SetTestIsRunning(false);
-  fprintf(stderr, "%s", proxy_->CaptureTree(false, false).c_str());
+  fprintf(stderr, "%s", proxy_ ? proxy_->CaptureTree(false, false).c_str()
+                               : dump_tree_.c_str());
 }
 
 void WebTestDelegateImpl::CloseRemainingWindows() {
   NOTIMPLEMENTED();
 }
 
 void WebTestDelegateImpl::DeleteAllCookies() {
   NOTIMPLEMENTED();
 }
 
@@ skipping 75 matching lines @@
   NOTIMPLEMENTED();
 }
 
 blink::WebPlugin* WebTestDelegateImpl::CreatePluginPlaceholder(
     blink::WebLocalFrame* frame,
     const blink::WebPluginParams& params) {
   NOTIMPLEMENTED();
   return nullptr;
 }
 
+void WebTestDelegateImpl::OnWebTestProxyBaseDestroy(
+    test_runner::WebTestProxyBase* base) {
+  DCHECK_EQ(proxy_, base);
+  dump_tree_ = proxy_->CaptureTree(false, false);
+  proxy_ = nullptr;
+}
+
 }  // namespace html_viewer