tracing: remove WatchEvent feature

content/public/browser/tracing_controller.h

 // Copyright 2013 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_TRACING_CONTROLLER_H_
 #define CONTENT_PUBLIC_BROWSER_TRACING_CONTROLLER_H_
 
 #include <stddef.h>
 
 #include <set>
@@ skipping 116 matching lines @@
   // set beforehand in case of key collision.
   virtual void AddMetadata(const base::DictionaryValue& metadata) = 0;
 
   // Get the maximum across processes of trace buffer percent full state.
   // When the TraceBufferUsage value is determined, the callback is
   // called.
   typedef base::Callback<void(float, size_t)> GetTraceBufferUsageCallback;
   virtual bool GetTraceBufferUsage(
       const GetTraceBufferUsageCallback& callback) = 0;
 
-  // |callback| will will be called every time the given event occurs on any
-  // process.
-  typedef base::Callback<void()> WatchEventCallback;
-  virtual bool SetWatchEvent(const std::string& category_name,
-                             const std::string& event_name,
-                             const WatchEventCallback& callback) = 0;
-
-  // Cancel the watch event. If tracing is enabled, this may race with the
-  // watch event callback.
-  virtual bool CancelWatchEvent() = 0;
-
   // Check if the tracing system is tracing
   virtual bool IsTracing() const = 0;
 
  protected:
   virtual ~TracingController() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_TRACING_CONTROLLER_H_