[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/schema_handler.cc

Index: content/browser/devtools/protocol/schema_handler.cc
diff --git a/content/browser/devtools/protocol/schema_handler.cc b/content/browser/devtools/protocol/schema_handler.cc
index 6583de68c6946f86fcaaf6b2cb3fe52153be46b9..6cf5b21db2518327f79d91799310454d9822e705 100644
--- a/content/browser/devtools/protocol/schema_handler.cc
+++ b/content/browser/devtools/protocol/schema_handler.cc
@@ -7,7 +7,8 @@
 namespace content {
 namespace protocol {
 
-SchemaHandler::SchemaHandler() {
+SchemaHandler::SchemaHandler()
+    : DevToolsDomainHandler(Schema::Metainfo::domainName) {
 }
 
 SchemaHandler::~SchemaHandler() {
@@ -17,10 +18,6 @@ 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.