Add the Windows.IsPinnedToTaskbar metric.

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

Index: chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
diff --git a/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc b/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
index 281945d5632b740b9d39d69e3894c66a87a1cf74..a75930e9e702e6b28e32b3a1ca50ff2bf43f3004 100644
--- a/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
+++ b/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
@@ -52,6 +52,7 @@
 
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
+#include "chrome/browser/shell_integration_win.h"
 #include "chrome/installer/util/google_update_settings.h"
 #endif  // defined(OS_WIN)
 
@@ -354,6 +355,13 @@ void ChromeBrowserMainExtraPartsMetrics::PostBrowserStart() {
       FROM_HERE,
       base::Bind(&RecordStartupMetricsOnBlockingPool),
       base::TimeDelta::FromSeconds(kStartupMetricsGatheringDelaySeconds));
+#if defined(OS_WIN)
+  content::BrowserThread::PostDelayedTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&shell_integration::win::RecordIsPinnedToTaskbarHistogram),
+      base::TimeDelta::FromSeconds(kStartupMetricsGatheringDelaySeconds));

[dcheng, 2016/07/01 05:46:55]

Nit: I think kStartupMetricsGatheringDelaySeconds can just be a base::TimeDelta
directly now: https://codereview.chromium.org/1976703005

[Patrick Monette, 2016/07/04 15:36:15]

Done.

+#endif  // defined(OS_WIN)
+
 
   display_count_ = display::Screen::GetScreen()->GetNumDisplays();
   UMA_HISTOGRAM_COUNTS_100("Hardware.Display.Count.OnStartup", display_count_);