tracing: remove WatchEvent feature

base/trace_event/trace_log.h

 // Copyright 2015 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 BASE_TRACE_EVENT_TRACE_LOG_H_
 #define BASE_TRACE_EVENT_TRACE_LOG_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 267 matching lines @@
       unsigned int flags);
 
   void UpdateTraceEventDuration(const unsigned char* category_group_enabled,
                                 const char* name,
                                 TraceEventHandle handle);
 
   void EndFilteredEvent(const unsigned char* category_group_enabled,
                         const char* name,
                         TraceEventHandle handle);
 
-  // For every matching event, the callback will be called.
-  typedef base::Callback<void()> WatchEventCallback;
-  void SetWatchEvent(const std::string& category_name,
-                     const std::string& event_name,
-                     const WatchEventCallback& callback);
-  // Cancel the watch event. If tracing is enabled, this may race with the
-  // watch event notification firing.
-  void CancelWatchEvent();
-
   int process_id() const { return process_id_; }
 
   uint64_t MangleEventId(uint64_t id);
 
   // Exposed for unittesting:
 
   // Allows deleting our singleton instance.
   static void DeleteForTesting();
 
   class BASE_EXPORT TraceEventFilter {
@@ skipping 189 matching lines @@
 
   TimeTicks buffer_limit_reached_timestamp_;
 
   // XORed with TraceID to make it unlikely to collide with other processes.
   unsigned long long process_id_hash_;
 
   int process_id_;
 
   TimeDelta time_offset_;
 
-  // Allow tests to wake up when certain events occur.
-  WatchEventCallback watch_event_callback_;
-  subtle::AtomicWord /* const unsigned char* */ watch_category_;
-  std::string watch_event_name_;
-
   subtle::AtomicWord /* Options */ trace_options_;
 
   TraceConfig trace_config_;
   TraceConfig::EventFilters enabled_event_filters_;
 
   ThreadLocalPointer<ThreadLocalEventBuffer> thread_local_event_buffer_;
   ThreadLocalBoolean thread_blocks_message_loop_;
   ThreadLocalBoolean thread_is_in_trace_event_;
 
   // Contains the message loops of threads that have had at least one event
@@ skipping 13 matching lines @@
   subtle::AtomicWord generation_;
   bool use_worker_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_TRACE_LOG_H_