tracing: remove WatchEvent feature

components/tracing/common/tracing_messages.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.
 
 // Multiply-included message header, no traditional include guard.
 
 #include <stdint.h>
 
 #include <string>
 #include <vector>
@@ skipping 42 matching lines @@
 
 // Sent to all child processes to disable trace event recording.
 IPC_MESSAGE_CONTROL0(TracingMsg_EndTracing)
 
 // Sent to all child processes to cancel trace event recording.
 IPC_MESSAGE_CONTROL0(TracingMsg_CancelTracing)
 
 // Sent to all child processes to get trace buffer fullness.
 IPC_MESSAGE_CONTROL0(TracingMsg_GetTraceLogStatus)
 
-// Sent to all child processes to set watch event.
-IPC_MESSAGE_CONTROL2(TracingMsg_SetWatchEvent,
-                     std::string /* category_name */,
-                     std::string /* event_name */)
-
-// Sent to all child processes to clear watch event.
-IPC_MESSAGE_CONTROL0(TracingMsg_CancelWatchEvent)
-
 // Sent to all child processes to request a local (current process) memory dump.
 IPC_MESSAGE_CONTROL1(TracingMsg_ProcessMemoryDumpRequest,
                      base::trace_event::MemoryDumpRequestArgs)
 
 // Reply to TracingHostMsg_GlobalMemoryDumpRequest, sent by the browser process.
 // This is to get the result of a global dump initiated by a child process.
 IPC_MESSAGE_CONTROL2(TracingMsg_GlobalMemoryDumpResponse,
                      uint64_t /* dump_guid */,
                      bool /* success */)
 
 IPC_MESSAGE_CONTROL4(TracingMsg_SetUMACallback,
                      std::string /* histogram_name */,
                      base::HistogramBase::Sample /* histogram_lower_value */,
                      base::HistogramBase::Sample /* histogram_uppwer_value */,
                      bool /* repeat */)
 
 IPC_MESSAGE_CONTROL1(TracingMsg_ClearUMACallback,
                      std::string /* histogram_name */)
 
-// Sent everytime when a watch event is matched.
-IPC_MESSAGE_CONTROL0(TracingHostMsg_WatchEventMatched)
-
 // Notify the browser that this child process supports tracing.
 IPC_MESSAGE_CONTROL0(TracingHostMsg_ChildSupportsTracing)
 
 // Reply from child processes acking TracingMsg_EndTracing.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_EndTracingAck,
                      std::vector<std::string> /* known_categories */)
 
 // Child processes send back trace data in JSON chunks.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_TraceDataCollected,
                      std::string /*json trace data*/)
 
 // Reply to TracingMsg_GetTraceLogStatus.
 IPC_MESSAGE_CONTROL1(
     TracingHostMsg_TraceLogStatusReply,
     base::trace_event::TraceLogStatus /*status of the trace log*/)
 
 // Sent to the browser to initiate a global memory dump from a child process.
 IPC_MESSAGE_CONTROL1(TracingHostMsg_GlobalMemoryDumpRequest,
                      base::trace_event::MemoryDumpRequestArgs)
 
 // Reply to TracingMsg_ProcessMemoryDumpRequest.
 IPC_MESSAGE_CONTROL2(TracingHostMsg_ProcessMemoryDumpResponse,
                      uint64_t /* dump_guid */,
                      bool /* success */)
 
 IPC_MESSAGE_CONTROL1(TracingHostMsg_TriggerBackgroundTrace,
                      std::string /* name */)
 
 IPC_MESSAGE_CONTROL0(TracingHostMsg_AbortBackgroundTrace)