Revert of Revert "Revert 237280 "Remove TraceController""

components/tracing/child_trace_message_filter.cc

Index: components/tracing/child_trace_message_filter.cc
diff --git a/components/tracing/child_trace_message_filter.cc b/components/tracing/child_trace_message_filter.cc
index d3875c7fa04a7bfa4a921c71164ef5d398194211..8a0e414c088b8e8f9adc643b3a54bb1e2560185b 100644
--- a/components/tracing/child_trace_message_filter.cc
+++ b/components/tracing/child_trace_message_filter.cc
@@ -19,11 +19,14 @@
 
 void ChildTraceMessageFilter::OnFilterAdded(IPC::Channel* channel) {
   channel_ = channel;
+  TraceLog::GetInstance()->SetNotificationCallback(
+      base::Bind(&ChildTraceMessageFilter::OnTraceNotification, this));
   channel_->Send(new TracingHostMsg_ChildSupportsTracing());
 }
 
 void ChildTraceMessageFilter::OnFilterRemoved() {
-  channel_ = NULL;
+  TraceLog::GetInstance()->SetNotificationCallback(
+      TraceLog::NotificationCallback());
 }
 
 bool ChildTraceMessageFilter::OnMessageReceived(const IPC::Message& message) {
@@ -107,22 +110,12 @@
 
 void ChildTraceMessageFilter::OnSetWatchEvent(const std::string& category_name,
                                               const std::string& event_name) {
-  TraceLog::GetInstance()->SetWatchEvent(
-      category_name, event_name,
-      base::Bind(&ChildTraceMessageFilter::OnWatchEventMatched, this));
+  TraceLog::GetInstance()->SetWatchEvent(category_name.c_str(),
+                                         event_name.c_str());
 }
 
 void ChildTraceMessageFilter::OnCancelWatchEvent() {
   TraceLog::GetInstance()->CancelWatchEvent();
-}
-
-void ChildTraceMessageFilter::OnWatchEventMatched() {
-  if (!ipc_message_loop_->BelongsToCurrentThread()) {
-    ipc_message_loop_->PostTask(FROM_HERE,
-        base::Bind(&ChildTraceMessageFilter::OnWatchEventMatched, this));
-    return;
-  }
-  channel_->Send(new TracingHostMsg_WatchEventMatched);
 }
 
 void ChildTraceMessageFilter::OnTraceDataCollected(
@@ -164,4 +157,14 @@
     channel_->Send(new TracingHostMsg_CaptureMonitoringSnapshotAck());
 }
 
+void ChildTraceMessageFilter::OnTraceNotification(int notification) {
+  if (!ipc_message_loop_->BelongsToCurrentThread()) {
+    ipc_message_loop_->PostTask(FROM_HERE,
+        base::Bind(&ChildTraceMessageFilter::OnTraceNotification, this,
+                   notification));
+    return;
+  }
+  channel_->Send(new TracingHostMsg_TraceNotification(notification));
+}
+
 }  // namespace tracing