Profiler-instrumentation of the startup time

chrome/app/chrome_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 "chrome/app/chrome_main_delegate.h"
 
+#include "base/profiler/scoped_tracker.h"
+#include "chrome/common/chrome_version_info.h"
 #include "content/public/app/content_main.h"
 
 #if defined(OS_WIN)
 #include "base/debug/dump_without_crashing.h"
 #include "base/win/win_util.h"
 #include "chrome/common/chrome_constants.h"
 
 #define DLLEXPORT __declspec(dllexport)
 
 // We use extern C for the prototype DLLEXPORT to avoid C++ name mangling.
@@ skipping 39 matching lines @@
   typedef void (__cdecl *DumpProcessFunction)();
   DumpProcessFunction DumpProcess = reinterpret_cast<DumpProcessFunction>(
       ::GetProcAddress(::GetModuleHandle(chrome::kBrowserProcessExecutableName),
           "DumpProcessWithoutCrash"));
   base::debug::SetDumpWithoutCrashingFunction(DumpProcess);
 #else
   params.argc = argc;
   params.argv = argv;
 #endif
 
+  // TODO(vadimt): Remove the switch statement below once crbug.com/453640 is
+  // fixed.
+  // Enable profiler instrumentation depending on the channel.
+  switch (chrome::VersionInfo::GetChannel()) {
+    case chrome::VersionInfo::CHANNEL_UNKNOWN:
+    case chrome::VersionInfo::CHANNEL_CANARY:
+      tracked_objects::ScopedTracker::Enable();

[Alexei Svitkine (slow), 2015/01/30 14:09:23]

Does this actually work?

My understanding (but maybe I'm wrong) is this code is n chrome.exe, while the
rest of the code is in chrome.dll.

I might be wrong, but I thought they linked in their own copies of 'base'' - so
calling this at this stage will not affect the one in the dll. If that's the
case, then you may need to call the copy of this function that's in the dll -
e.g. similar to how DumpProcessFunction is called above.

But as I said, it is possible that I'm wrong. Can you check the above?

[vadimt, 2015/01/30 16:14:47]

This works  both in Debug and Release builds.

+      break;
+
+    case chrome::VersionInfo::CHANNEL_DEV:
+    case chrome::VersionInfo::CHANNEL_BETA:
+    case chrome::VersionInfo::CHANNEL_STABLE:
+      // Don't enable instrumentation.
+      break;
+  }
+
   int rv = content::ContentMain(params);
 
 #if defined(OS_WIN)
   base::win::SetShouldCrashOnProcessDetach(false);
 #endif
 
   return rv;
 }