[DevTools] Migrate from AgentStateCallbacks to DevToolsAgentHostObserver.

content/browser/devtools/render_frame_devtools_agent_host.cc

Index: content/browser/devtools/render_frame_devtools_agent_host.cc
diff --git a/content/browser/devtools/render_frame_devtools_agent_host.cc b/content/browser/devtools/render_frame_devtools_agent_host.cc
index ebf711133d6cf875f8fc8a8fc5f4a7b152f2f387..df0b440b89b0822cc9dec6d2abd963683bb71e27 100644
--- a/content/browser/devtools/render_frame_devtools_agent_host.cc
+++ b/content/browser/devtools/render_frame_devtools_agent_host.cc
@@ -533,10 +533,6 @@ void RenderFrameDevToolsAgentHost::OnClientAttached() {
 
   frame_trace_recorder_.reset(new DevToolsFrameTraceRecorder());
   CreatePowerSaveBlocker();
-
-  // TODO(kaznacheev): Move this call back to DevToolsManager when
-  // extensions::ProcessManager no longer relies on this notification.
-  DevToolsAgentHostImpl::NotifyCallbacks(this, true);
 }
 
 void RenderFrameDevToolsAgentHost::OnClientDetached() {
@@ -553,10 +549,6 @@ void RenderFrameDevToolsAgentHost::OnClientDetached() {
   tracing_handler_->Detached();
   frame_trace_recorder_.reset();
   in_navigation_protocol_message_buffer_.clear();
-
-  // TODO(kaznacheev): Move this call back to DevToolsManager when
-  // extensions::ProcessManager no longer relies on this notification.
-  DevToolsAgentHostImpl::NotifyCallbacks(this, false);
 }
 
 RenderFrameDevToolsAgentHost::~RenderFrameDevToolsAgentHost() {