[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/system_info_handler.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/browser/devtools/protocol/system_info_handler.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 156 matching lines @@
     GpuDataManager::GetInstance()->RemoveObserver(this);
     SendGetInfoResponse(std::move(callback_));
     delete this;
   }
 
  private:
   std::unique_ptr<GetInfoCallback> callback_;
   base::WeakPtrFactory<SystemInfoHandlerGpuObserver> weak_factory_;
 };
 
-SystemInfoHandler::SystemInfoHandler() {
+SystemInfoHandler::SystemInfoHandler()
+    : DevToolsDomainHandler(SystemInfo::Metainfo::domainName) {
 }
 
 SystemInfoHandler::~SystemInfoHandler() {
 }
 
 void SystemInfoHandler::Wire(UberDispatcher* dispatcher) {
   SystemInfo::Dispatcher::wire(dispatcher, this);
 }
 
-Response SystemInfoHandler::Disable() {
-  return Response::OK();
-}
-
 void SystemInfoHandler::GetInfo(
     std::unique_ptr<GetInfoCallback> callback) {
   std::string reason;
   if (!GpuDataManager::GetInstance()->GpuAccessAllowed(&reason) ||
       GpuDataManager::GetInstance()->IsEssentialGpuInfoAvailable() ||
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kGpuTestingNoCompleteInfoCollection)) {
     // The GpuDataManager already has all of the information needed to make
     // GPU-based blacklisting decisions. Post a task to give it to the
     // client asynchronously.
     //
     // Waiting for complete GPU info in the if-test above seems to
     // frequently hit internal timeouts in the launching of the unsandboxed
     // GPU process in debug builds on Windows.
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
         base::Bind(&SendGetInfoResponse, base::Passed(std::move(callback))));
   } else {
     // We will be able to get more information from the GpuDataManager.
     // Register a transient observer with it to call us back when the
     // information is available.
     new SystemInfoHandlerGpuObserver(std::move(callback));
   }
 }
 
 }  // namespace protocol
 }  // namespace content