[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..0100d6f9bd3910cb0a7030b53d2c69487d773b61 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() {
@@ -17,6 +18,9 @@ void SchemaHandler::Wire(UberDispatcher* dispatcher) {
   Schema::Dispatcher::wire(dispatcher, this);
 }
 
+void SchemaHandler::SetRenderFrameHost(RenderFrameHostImpl* host) {
+}
+
 Response SchemaHandler::Disable() {
   return Response::OK();
 }