Add histogram to track Mojo shell / renderer connection init

content/renderer/renderer_main.cc

 // 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.
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/debug/debugger.h"
 #include "base/debug/leak_annotations.h"
 #include "base/feature_list.h"
 #include "base/i18n/rtl.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/field_trial.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/pending_task.h"
 #include "base/strings/string_util.h"
 #include "base/sys_info.h"
 #include "base/threading/platform_thread.h"
+#include "base/timer/elapsed_timer.h"
 #include "base/timer/hi_res_timer_manager.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "components/scheduler/renderer/renderer_scheduler.h"
 #include "content/child/child_process.h"
 #include "content/common/content_constants_internal.h"
 #include "content/common/mojo/mojo_shell_connection_impl.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/renderer/content_renderer_client.h"
@@ skipping 54 matching lines @@
   // Don't use the TRACE_EVENT0 macro because the tracing infrastructure doesn't
   // expect synchronous events around the main loop of a thread.
   TRACE_EVENT_ASYNC_BEGIN0("startup", "RendererMain", 0);
 
   base::trace_event::TraceLog::GetInstance()->SetProcessName("Renderer");
   base::trace_event::TraceLog::GetInstance()->SetProcessSortIndex(
       kTraceEventRendererProcessSortIndex);
 
   const base::CommandLine& parsed_command_line = parameters.command_line;
 
-  MojoShellConnectionImpl::Create();
+  {
+    base::ElapsedTimer timer;
+    MojoShellConnectionImpl::Create();
+    UMA_HISTOGRAM_TIMES("Mojo.Shell.RenderProcessInitializationTime",
+                        timer.Elapsed());
+  }
 
 #if defined(OS_MACOSX)
   base::mac::ScopedNSAutoreleasePool* pool = parameters.autorelease_pool;
 #endif  // OS_MACOSX
 
 #if defined(OS_CHROMEOS)
   // As Zygote process starts up earlier than browser process gets its own
   // locale (at login time for Chrome OS), we have to set the ICU default
   // locale for renderer process here.
   // ICU locale will be used for fallback font selection etc.
@@ skipping 120 matching lines @@
     // ignore shutdown-only leaks.
     __lsan_do_leak_check();
 #endif
   }
   platform.PlatformUninitialize();
   TRACE_EVENT_ASYNC_END0("startup", "RendererMain", 0);
   return 0;
 }
 
 }  // namespace content