WebViewTestProxyBase: clear out main test delegate upon destruction.

content/shell/test_runner/mock_web_speech_recognizer.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/mock_web_speech_recognizer.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 142 matching lines @@
 }  // namespace
 
 MockWebSpeechRecognizer::MockWebSpeechRecognizer()
     : client_(nullptr),
       was_aborted_(false),
       task_queue_running_(false),
       delegate_(0),
       weak_factory_(this) {}
 
 MockWebSpeechRecognizer::~MockWebSpeechRecognizer() {
-  ClearTaskQueue();
+  SetDelegate(nullptr);
 }
 
 bool MockWebSpeechRecognizer::Task::isNewContextTask() const {
   return false;
 }
 
 void MockWebSpeechRecognizer::SetDelegate(WebTestDelegate* delegate) {
   delegate_ = delegate;
+  // No delegate to forward to, clear out pending tasks.
+  if (!delegate_)
+    ClearTaskQueue();
 }
 
 void MockWebSpeechRecognizer::SetClientContext(
     const blink::WebSpeechRecognitionHandle& handle,
     blink::WebSpeechRecognizerClient* client) {
   handle_ = handle;
   client_ = client;
 }
 
 void MockWebSpeechRecognizer::start(
@@ skipping 138 matching lines @@
 
 bool MockWebSpeechRecognizer::HasPendingNewContextTasks() const {
   for (auto* task : task_queue_) {
     if (task->isNewContextTask())
       return true;
   }
   return false;
 }
 
 }  // namespace test_runner