Implement about:tracing UI for the sampling profiler (Chromium part)

content/public/browser/trace_controller.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_TRACE_CONTROLLER_H_
 #define CONTENT_PUBLIC_BROWSER_TRACE_CONTROLLER_H_
 
 #include "base/debug/trace_event.h"
 #include "content/common/content_export.h"
 
@@ skipping 44 matching lines @@
   // asynchronously ask all child processes to flush any pending trace data.
   //
   // Once all child processes have acked the EndTracing request,
   // TraceSubscriber will be called with OnEndTracingComplete.
   //
   // If a previous call to EndTracingAsync is already pending,
   //   or if another subscriber is tracing,
   //   EndTracingAsync will return false meaning it failed.
   virtual bool EndTracingAsync(TraceSubscriber* subscriber) = 0;
 
+  virtual bool BeginContinuousSamplingTracing(TraceSubscriber* subscriber) = 0;
+  virtual bool EndContinuousSamplingTracing(TraceSubscriber* subscriber) = 0;
+  virtual bool ShowContinuousSamplingTracingAsync(
+      TraceSubscriber* subscriber) = 0;
+
   // Get the maximum across processes of trace buffer percent full state.
   // When the TraceBufferPercentFull value is determined,
   // subscriber->OnTraceBufferPercentFullReply is called.
   // When any child process reaches 100% full, the TraceController will end
   // tracing, and call TraceSubscriber::OnEndTracingComplete.
   // GetTraceBufferPercentFullAsync fails in the following conditions:
   //   trace is ending or disabled;
   //   a previous call to GetTraceBufferPercentFullAsync is pending; or
   //   the caller is not the current subscriber.
   virtual bool GetTraceBufferPercentFullAsync(TraceSubscriber* subscriber) = 0;
@@ skipping 20 matching lines @@
   virtual bool GetKnownCategoryGroupsAsync(TraceSubscriber* subscriber) = 0;
 
  protected:
   virtual ~TraceController() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_TRACE_CONTROLLER_H_