Add support for Blimp engine metrics reporting in development.

chrome/browser/browser_process_impl.cc

Index: chrome/browser/browser_process_impl.cc
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 12512d561f1b5fc69bb1e1c3f6d650502942e399..2d211b75344ead77f9adeb529f42ccdc173c768e 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -853,8 +853,16 @@ void BrowserProcessImpl::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterStringPref(prefs::kHardwareKeyboardLayout,
                                std::string());
 #endif  // defined(OS_CHROMEOS)
+
+#if defined(ENABLE_REPORTING_HEADLESS)

[maniscalco, 2016/03/08 16:38:22]

Was leaving the word blimp out of the #define an explicit decision?  I'm
wondering because we have this is_headless GN arg.  If the is_headless stuff
started using ENABLE_REPORTING_HEADLESS would that be a good thing or bad thing?
 In other words, I'm wondering if this is the #define for just blimp or for all
headless things that report UMA.

[Jess, 2016/03/08 18:29:09]

Good point.  I think I was trying to use to variable naming to explain why it
would be used. Given the added comment it doesn't make much sense and could
easily be confused with is headless.

Renamed.

+  // Enables reporting for the (headless) blimp engine. Defined in
+  // components/metrics/BUILD.gn
+  registry->RegisterBooleanPref(metrics::prefs::kMetricsReportingEnabled, true);
+#else
   registry->RegisterBooleanPref(metrics::prefs::kMetricsReportingEnabled,
                                 GoogleUpdateSettings::GetCollectStatsConsent());
+#endif // defined(ENABLE_REPORTING_HEADLESS)
+
 #if BUILDFLAG(ANDROID_JAVA_UI)
   registry->RegisterBooleanPref(
       prefs::kCrashReportingEnabled, false);