Implements AddStartupEventsForTelemetry() in startup_metric_utils.cc for in-coming startup telemetry

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index fb18e51d07c43297a9c9d663aa0e87f11d52ade0..dcd8136962f0dd8db133bd0c548631ebe7f1e391 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -1654,6 +1654,7 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
   // Most general initialization is behind us, but opening a
   // tab and/or session restore and such is still to be done.
   base::TimeTicks browser_open_start = base::TimeTicks::Now();
+  TRACE_EVENT_BEGIN0("startup", "Startup.BrowserOpenTabs");
 
   // We are in regular browser boot sequence. Open initial tabs and enter the
   // main message loop.
@@ -1704,6 +1705,8 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
     const base::TimeDelta delta = base::TimeTicks::Now() - browser_open_start;
     startup_metric_utils::RecordBrowserOpenTabsDelta(delta);
 
+    TRACE_EVENT_END0("startup", "Startup.BrowserOpenTabs");

[gab, 2015/11/10 19:30:53]

I like these, except I'm not convinced they belong in this specific change?
Perhaps split it into multiple dedicated CLs?

[gabadie, 2015/11/12 08:57:20]

Done.

+
     // If we're running tests (ui_task is non-null), then we don't want to
     // call RequestLanguageList or StartRepeatedVariationsSeedFetch or
     // RequestLanguageList