[DevTools] Cleanup DevToolsTarget and DevToolsManagerDelegate after moving to devtools_discovery.

android_webview/browser/aw_dev_tools_manager_delegate.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 "android_webview/browser/aw_dev_tools_manager_delegate.h"
-
-#include "components/devtools_discovery/devtools_discovery_manager.h"
-#include "content/public/browser/devtools_target.h"
-
-namespace android_webview {
-
-AwDevToolsManagerDelegate::AwDevToolsManagerDelegate() {
-}
-
-AwDevToolsManagerDelegate::~AwDevToolsManagerDelegate() {
-}
-
-base::DictionaryValue* AwDevToolsManagerDelegate::HandleCommand(
-    content::DevToolsAgentHost* agent_host,
-    base::DictionaryValue* command_dict) {
-  return NULL;
-}
-
-void AwDevToolsManagerDelegate::EnumerateTargets(TargetCallback callback) {
-  TargetList targets;
-  devtools_discovery::DevToolsDiscoveryManager* discovery_manager =
-      devtools_discovery::DevToolsDiscoveryManager::GetInstance();
-  for (const auto& descriptor : discovery_manager->GetDescriptors())
-    targets.push_back(descriptor);
-  callback.Run(targets);
-}
-
-std::string AwDevToolsManagerDelegate::GetPageThumbnailData(const GURL&) {
-  return "";
-}
-
-scoped_ptr<content::DevToolsTarget> AwDevToolsManagerDelegate::CreateNewTarget(
-    const GURL&) {
-  return scoped_ptr<content::DevToolsTarget>();
-}
-
-}  // namespace android_webview