Profiler-instrumentation of the startup time

chrome/app/chrome_main.cc

Index: chrome/app/chrome_main.cc
diff --git a/chrome/app/chrome_main.cc b/chrome/app/chrome_main.cc
index 360b7e5def0c4a6700bf22110fe0ef2a7d5f356f..b80d1dfcb623f1dd8c9f7aeeedbd88ae4b25fcba 100644
--- a/chrome/app/chrome_main.cc
+++ b/chrome/app/chrome_main.cc
@@ -4,6 +4,8 @@
 
 #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)
@@ -63,6 +65,22 @@ int ChromeMain(int argc, const char** argv) {
   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)