Slow Reports - Add message filter to trigger background traces from child processes.

components/tracing/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 <string>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/metrics/histogram.h"
 #include "base/sync_socket.h"
 #include "base/trace_event/memory_dump_request_args.h"
 #include "base/trace_event/trace_event_impl.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_message_macros.h"
 #include "ipc/ipc_message_utils.h"
 #include "ipc/ipc_platform_file.h"
 
 #define IPC_MESSAGE_START TracingMsgStart
 
@@ skipping 48 matching lines @@
 // 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 /* dump_guid */,
                      bool /* success */)
 
+IPC_MESSAGE_CONTROL2(TracingMsg_SetUMACallback,
+                     std::string /* histogram_name */,
+                     base::HistogramBase::Sample /* histogram_value */)
+
+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 */)
 
@@ skipping 15 matching lines @@
     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 /* dump_guid */,
                      bool /* success */)
+
+IPC_MESSAGE_CONTROL1(TracingHostMsg_TriggerBackgroundTrace,
+                     std::string /* name */)