Instrument EDK sync Broker initialization

mojo/edk/system/node_controller.cc

 // Copyright 2016 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.
 
 #include "mojo/edk/system/node_controller.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/process/process_handle.h"
+#include "base/timer/elapsed_timer.h"
 #include "crypto/random.h"
 #include "mojo/edk/embedder/embedder_internal.h"
 #include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/system/broker.h"
 #include "mojo/edk/system/broker_host.h"
 #include "mojo/edk/system/core.h"
 #include "mojo/edk/system/ports_message.h"
 
 namespace mojo {
 namespace edk {
@@ skipping 96 matching lines @@
                  base::Unretained(this),
                  process_handle,
                  base::Passed(&platform_handle)));
 }
 
 void NodeController::ConnectToParent(ScopedPlatformHandle platform_handle) {
 // TODO(amistry): Consider the need for a broker on Windows.
 #if defined(OS_POSIX)
   // On posix, use the bootstrap channel for the broker and receive the node's
   // channel synchronously as the first message from the broker.
+  base::ElapsedTimer timer;
   broker_.reset(new Broker(std::move(platform_handle)));
   platform_handle = broker_->GetParentPlatformHandle();
+  UMA_HISTOGRAM_TIMES("Mojo.System.GetParentPlatformHandleSyncTime",
+                      timer.Elapsed());
 #endif
 
   io_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&NodeController::ConnectToParentOnIOThread,
                  base::Unretained(this),
                  base::Passed(&platform_handle)));
 }
 
 void NodeController::SetPortObserver(
@@ skipping 761 matching lines @@
     shutdown_callback_.Reset();
   }
 
   DCHECK(!callback.is_null());
 
   callback.Run();
 }
 
 }  // namespace edk
 }  // namespace mojo