Revert 227354 "Revert "Implement TracingController::{Enable,Disa..."

The original CL was reverted because it increased the binary size of
nacl-helper/data by 0.45%, but the increase was just 128 bytes.
So I'll reland this CL, supressing the size failure.

> Revert "Implement TracingController::{Enable,Disable,Capture}Monitoring"
> Revert "Fix failures in chrome os after r227262"
> Revert "Fix the content_browser breakage after r227269"
> 
> Caused sizes regression on linux for nacl-helper-data.
> 
> TBR=haraken
> BUG=304789
> 
> > Implement TracingController::{Enable,Disable,Capture}Monitoring
> >
> > This CL implements TracingController::EnableMonitoring,
> > TracingController::DisableMonitoring and
> > TracingController::CaptureMonitoringSnapshot.
> >
> > BUG=241743
> > TEST=base_unittests::TraceEventTestFixture.TraceContinuousSampling,
> > content_browsertests::TracingControllerTest.EnableCaptureAndDisableMonitoring
> >
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=226701
> >
> > R=dsinclair@chromium.org, joi@chromium.org, nduca@chromium.org, tsepez@chromium.org
> >
> > Review URL: https://codereview.chromium.org/23531042
> 
> Review URL: https://codereview.chromium.org/26294003

TBR=justinlin@chromium.org

Review URL: https://codereview.chromium.org/26272005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227413 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 80 insertions, 3 deletions

diff --git a/components/tracing/child_trace_message_filter.cc b/components/tracing/child_trace_message_filter.cc
index 8310ec5..9925f3f 100644
--- a/components/tracing/child_trace_message_filter.cc
+++ b/components/tracing/child_trace_message_filter.cc
@@ -34,6 +34,10 @@ bool ChildTraceMessageFilter::OnMessageReceived(const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(ChildTraceMessageFilter, message)
     IPC_MESSAGE_HANDLER(TracingMsg_BeginTracing, OnBeginTracing)
     IPC_MESSAGE_HANDLER(TracingMsg_EndTracing, OnEndTracing)
+    IPC_MESSAGE_HANDLER(TracingMsg_EnableMonitoring, OnEnableMonitoring)
+    IPC_MESSAGE_HANDLER(TracingMsg_DisableMonitoring, OnDisableMonitoring)
+    IPC_MESSAGE_HANDLER(TracingMsg_CaptureMonitoringSnapshot,
+                        OnCaptureMonitoringSnapshot)
     IPC_MESSAGE_HANDLER(TracingMsg_GetTraceBufferPercentFull,
                         OnGetTraceBufferPercentFull)
     IPC_MESSAGE_HANDLER(TracingMsg_SetWatchEvent, OnSetWatchEvent)
@@ -73,6 +77,33 @@ void ChildTraceMessageFilter::OnEndTracing() {
       base::Bind(&ChildTraceMessageFilter::OnTraceDataCollected, this));
 }
 
+void ChildTraceMessageFilter::OnEnableMonitoring(
+    const std::string& category_filter_str,
+    base::TimeTicks browser_time,
+    int options) {
+  TraceLog::GetInstance()->SetEnabled(
+      base::debug::CategoryFilter(category_filter_str),
+      static_cast<base::debug::TraceLog::Options>(options));
+}
+
+void ChildTraceMessageFilter::OnDisableMonitoring() {
+  TraceLog::GetInstance()->SetDisabled();
+}
+
+void ChildTraceMessageFilter::OnCaptureMonitoringSnapshot() {
+  // Flush will generate one or more callbacks to
+  // OnMonitoringTraceDataCollected. It's important that the last
+  // OnMonitoringTraceDataCollected gets called before
+  // CaptureMonitoringSnapshotAck below. We are already on the IO thread,
+  // so the OnMonitoringTraceDataCollected calls will not be deferred.
+  TraceLog::GetInstance()->FlushButLeaveBufferIntact(
+      base::Bind(&ChildTraceMessageFilter::
+                 OnMonitoringTraceDataCollected,
+                 this));
+
+  channel_->Send(new TracingHostMsg_CaptureMonitoringSnapshotAck());
+}
+
 void ChildTraceMessageFilter::OnGetTraceBufferPercentFull() {
   float bpf = TraceLog::GetInstance()->GetBufferPercentFull();
 
@@ -109,6 +140,22 @@ void ChildTraceMessageFilter::OnTraceDataCollected(
   }
 }
 
+void ChildTraceMessageFilter::OnMonitoringTraceDataCollected(
+     const scoped_refptr<base::RefCountedString>& events_str_ptr,
+     bool has_more_events) {
+  if (!ipc_message_loop_->BelongsToCurrentThread()) {
+    ipc_message_loop_->PostTask(FROM_HERE,
+        base::Bind(&ChildTraceMessageFilter::
+                   OnMonitoringTraceDataCollected,
+                   this,
+                   events_str_ptr,
+                   has_more_events));
+    return;
+  }
+  channel_->Send(new TracingHostMsg_MonitoringTraceDataCollected(
+      events_str_ptr->data()));
+}
+
 void ChildTraceMessageFilter::OnTraceNotification(int notification) {
   if (!ipc_message_loop_->BelongsToCurrentThread()) {
     ipc_message_loop_->PostTask(FROM_HERE,
diff --git a/components/tracing/child_trace_message_filter.h b/components/tracing/child_trace_message_filter.h
index 9f10b4a..cbd300f 100644
--- a/components/tracing/child_trace_message_filter.h
+++ b/components/tracing/child_trace_message_filter.h
@@ -32,8 +32,13 @@ class ChildTraceMessageFilter : public IPC::ChannelProxy::MessageFilter {
   // Message handlers.
   void OnBeginTracing(const std::string& category_filter_str,
                       base::TimeTicks browser_time,
-                      int mode);
+                      int options);
   void OnEndTracing();
+  void OnEnableMonitoring(const std::string& category_filter_str,
+                          base::TimeTicks browser_time,
+                          int options);
+  void OnDisableMonitoring();
+  void OnCaptureMonitoringSnapshot();
   void OnGetTraceBufferPercentFull();
   void OnSetWatchEvent(const std::string& category_name,
                        const std::string& event_name);
@@ -43,6 +48,11 @@ class ChildTraceMessageFilter : public IPC::ChannelProxy::MessageFilter {
   void OnTraceDataCollected(
       const scoped_refptr<base::RefCountedString>& events_str_ptr,
       bool has_more_events);
+
+  void OnMonitoringTraceDataCollected(
+      const scoped_refptr<base::RefCountedString>& events_str_ptr,
+      bool has_more_events);
+
   void OnTraceNotification(int notification);
 
   IPC::Channel* channel_;
diff --git a/components/tracing/tracing_messages.h b/components/tracing/tracing_messages.h
index 9beb7e1..25b45bd 100644
--- a/components/tracing/tracing_messages.h
+++ b/components/tracing/tracing_messages.h
@@ -24,6 +24,18 @@ IPC_MESSAGE_CONTROL3(TracingMsg_BeginTracing,
 // Sent to all child processes to disable trace event recording.
 IPC_MESSAGE_CONTROL0(TracingMsg_EndTracing)
 
+// Sent to all child processes to start monitoring.
+IPC_MESSAGE_CONTROL3(TracingMsg_EnableMonitoring,
+                     std::string /*  category_filter_str */,
+                     base::TimeTicks /* browser_time */,
+                     int /* base::debug::TraceLog::Options */)
+
+// Sent to all child processes to stop monitoring..
+IPC_MESSAGE_CONTROL0(TracingMsg_DisableMonitoring)
+
+// Sent to all child processes to capture the current monitorint snapshot.
+IPC_MESSAGE_CONTROL0(TracingMsg_CaptureMonitoringSnapshot)
+
 // Sent to all child processes to get trace buffer fullness.
 IPC_MESSAGE_CONTROL0(TracingMsg_GetTraceBufferPercentFull)
 
@@ -38,18 +50,26 @@ IPC_MESSAGE_CONTROL0(TracingMsg_CancelWatchEvent)
 // Notify the browser that this child process supports tracing.
 IPC_MESSAGE_CONTROL0(TracingHostMsg_ChildSupportsTracing)
 
-// Reply from child processes acking ChildProcessMsg_TraceChangeStatus(false).
+// Reply from child processes acking TracingMsg_EndTracing.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_EndTracingAck,
                      std::vector<std::string> /* known_categories */)
 
+// Reply from child processes acking TracingMsg_CaptureMonitoringSnapshot.
+IPC_MESSAGE_CONTROL0(TracingHostMsg_CaptureMonitoringSnapshotAck)
+
 // Sent if the trace buffer becomes full.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_TraceNotification,
                      int /* base::debug::TraceLog::Notification */)
 
-// Child processes send trace data back in JSON chunks.
+// Child processes send back trace data in JSON chunks.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_TraceDataCollected,
                      std::string /*json trace data*/)
 
+// Child processes send back trace data of the current monitoring
+// in JSON chunks.
+IPC_MESSAGE_CONTROL1(TracingHostMsg_MonitoringTraceDataCollected,
+                     std::string /*json trace data*/)
+
 // Reply to TracingMsg_GetTraceBufferPercentFull.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_TraceBufferPercentFullReply,
                      float /*trace buffer percent full*/)