[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/schema_handler.cc

 // Copyright 2016 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/schema_handler.h"
 
 namespace content {
 namespace protocol {
 
-SchemaHandler::SchemaHandler() {
+SchemaHandler::SchemaHandler()
+    : DevToolsDomainHandler(Schema::Metainfo::domainName) {
 }
 
 SchemaHandler::~SchemaHandler() {
 }
 
 void SchemaHandler::Wire(UberDispatcher* dispatcher) {
   Schema::Dispatcher::wire(dispatcher, this);
 }
 
-Response SchemaHandler::Disable() {
-  return Response::OK();
-}
-
 Response SchemaHandler::GetDomains(
     std::unique_ptr<protocol::Array<Schema::Domain>>* domains) {
   // TODO(kozyatisnkiy): get this from the target instead of hardcoding a list.
   static const char kVersion[] = "1.2";
   static const char* kDomains[] = {
     "Inspector", "Memory", "Page", "Rendering", "Emulation", "Security",
     "Network", "Database", "IndexedDB", "CacheStorage", "DOMStorage", "CSS",
     "ApplicationCache", "DOM", "IO", "DOMDebugger", "ServiceWorker",
     "Input", "LayerTree", "DeviceOrientation", "Tracing", "Animation",
     "Accessibility", "Storage", "Log", "Runtime", "Debugger",
     "Profiler", "HeapProfiler", "Schema", "Target"
   };
   *domains = protocol::Array<Schema::Domain>::create();
   for (size_t i = 0; i < arraysize(kDomains); ++i) {
     (*domains)->addItem(Schema::Domain::Create()
         .SetName(kDomains[i])
         .SetVersion(kVersion)
         .Build());
   }
   return Response::OK();
 }
 
 }  // namespace protocol
 }  // namespace content