Implement a poor man's PostAfterStartupTask() function.

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

 // Copyright (c) 2013 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/browser/metrics/chrome_browser_main_extra_parts_metrics.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 247 matching lines @@
 
   display_count_ = gfx::Screen::GetNativeScreen()->GetNumDisplays();
   UMA_HISTOGRAM_COUNTS_100("Hardware.Display.Count.OnStartup", display_count_);
   gfx::Screen::GetNativeScreen()->AddObserver(this);
   is_screen_observer_ = true;
 
 #if !defined(OS_ANDROID)
   first_web_contents_profiler_ =
       FirstWebContentsProfiler::CreateProfilerForFirstWebContents(this).Pass();
 #endif  // !defined(OS_ANDROID)
+  if (!first_web_contents_profiler_)
+    chrome::SetBrowserStartupIsComplete();
 }
 
 void ChromeBrowserMainExtraPartsMetrics::OnDisplayAdded(
     const gfx::Display& new_display) {
   EmitDisplaysChangedMetric();
 }
 
 void ChromeBrowserMainExtraPartsMetrics::OnDisplayRemoved(
     const gfx::Display& old_display) {
   EmitDisplaysChangedMetric();
 }
 
 void ChromeBrowserMainExtraPartsMetrics::OnDisplayMetricsChanged(
     const gfx::Display& display,
     uint32_t changed_metrics) {
 }
 
 void ChromeBrowserMainExtraPartsMetrics::ProfilerFinishedCollectingMetrics() {
   first_web_contents_profiler_.reset();
+
+  // TODO(michaeln): Revisit this in light of session restore, for now
+  // claim complete after the first page loads.
+  chrome::SetBrowserStartupIsComplete();

[gab, 2015/03/10 15:00:32]

Doesn't feel like ExtraPartsMetrics is the right place for this as it doesn't
have to do with metrics.

[michaeln, 2015/03/10 19:46:26]

Ditto any guidance.

I picked this location because this class and the FirstWebContentsProfiler are
responsible for the Startup.FirstWebContents.MainFrameLoad stat. That's exactly
what i'd like to consider 'isStartedUp' for now. These classes are also
responsible for how that stat is different on android (it's not logged there),
so its more clear why/what is different about the the startup compeltion flag
for android too.

[gab, 2015/03/10 19:55:27]

Then perhaps put it directly in FirstWebContentsProfiler besides the metric
logging? Makes it feel like that's repurposing FirstWebContentsProfiler a bit
beyond strictly "profiling", but that's not too bad IMO (we can rename the class
later if we care).

[michaeln, 2015/03/20 00:21:27]

I put it directly into ChromeBrowserMainParts, nothing extra needed.

 }
 
 void ChromeBrowserMainExtraPartsMetrics::EmitDisplaysChangedMetric() {
   int display_count = gfx::Screen::GetNativeScreen()->GetNumDisplays();
   if (display_count != display_count_) {
     display_count_ = display_count;
     UMA_HISTOGRAM_COUNTS_100("Hardware.Display.Count.OnChange", display_count_);
   }
 }
 
 namespace chrome {
 
 void AddMetricsExtraParts(ChromeBrowserMainParts* main_parts) {
   main_parts->AddParts(new ChromeBrowserMainExtraPartsMetrics());
 }
 
 }  // namespace chrome