[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/tracing_handler.cc

Index: content/browser/devtools/protocol/tracing_handler.cc
diff --git a/content/browser/devtools/protocol/tracing_handler.cc b/content/browser/devtools/protocol/tracing_handler.cc
index eb6f29cacbe8aaa93e24fc0854981db228200daf..e8f0e95d7d016b6309921a574147e8a831fa2b12 100644
--- a/content/browser/devtools/protocol/tracing_handler.cc
+++ b/content/browser/devtools/protocol/tracing_handler.cc
@@ -118,7 +118,8 @@ class DevToolsStreamEndpoint : public TraceDataEndpoint {
 TracingHandler::TracingHandler(TracingHandler::Target target,
                                int frame_tree_node_id,
                                DevToolsIOContext* io_context)
-    : target_(target),
+    : DevToolsDomainHandler(Tracing::Metainfo::domainName),
+      target_(target),
       io_context_(io_context),
       frame_tree_node_id_(frame_tree_node_id),
       did_initiate_recording_(false),
@@ -133,6 +134,9 @@ void TracingHandler::Wire(UberDispatcher* dispatcher) {
   Tracing::Dispatcher::wire(dispatcher, this);
 }
 
+void TracingHandler::SetRenderFrameHost(RenderFrameHostImpl* host) {
+}
+
 Response TracingHandler::Disable() {
   if (did_initiate_recording_)
     StopTracing(scoped_refptr<TracingController::TraceDataSink>());