Adding support for sampling crashes in Chrome on Windows.

chrome/install_static/install_util.cc

Index: chrome/install_static/install_util.cc
diff --git a/chrome/install_static/install_util.cc b/chrome/install_static/install_util.cc
index c31b90e8927cd71f4cedf026d3b44da0f2112046..66694b77508abe0df1e49378e7703348f0ac434f 100644
--- a/chrome/install_static/install_util.cc
+++ b/chrome/install_static/install_util.cc
@@ -55,6 +55,9 @@ const wchar_t kAppGuidGoogleChrome[] =
 const wchar_t kAppGuidGoogleBinaries[] =
     L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
 
+const wchar_t kChromeMetrics[] = L"\\MetricsReporting";

[Alexei Svitkine (slow), 2016/08/10 21:49:33]

Are just using this for the one sub-key? Seems strange given that usagestats
above isn't under this.

I would just put the key below next to usagestats and not have the intermediate
dir. Unless there's a good reason for this grouping?

[jwd, 2016/08/11 21:41:02]

Done.

+const wchar_t kChromeStatsSampleKey[] = L"usagestatsinsample";

[Alexei Svitkine (slow), 2016/08/10 21:49:33]

I know there's no comments here currently, but please add some about this to
explain what this means and what possible values it can have. Or in the header
file I guess.

[jwd, 2016/08/11 21:41:02]

Done.

+
 const wchar_t kHeadless[] = L"CHROME_HEADLESS";
 const wchar_t kShowRestart[] = L"CHROME_CRASHED";
 const wchar_t kRestartInfo[] = L"CHROME_RESTART";
@@ -271,6 +274,17 @@ bool GetCollectStatsConsentImpl(const std::wstring& exe_path) {
           out_value == 1);
 }
 
+bool GetCollectStatsInSampleImpl(const std::wstring& exe_path) {
+  std::wstring registry_path = L"Software\\";

[Alexei Svitkine (slow), 2016/08/10 21:49:33]

Seems strange to have this hardcoded. Can this be a constant? Or maybe a
function that returns the chrome install registry path so each function doesn't
need to append it themselves.

[jwd, 2016/08/11 21:41:02]

Done.

+  registry_path += GetChromeInstallSubDirectory();
+  registry_path += kChromeMetrics;
+
+  DWORD out_value = 0;
+  return (nt::QueryRegValueDWORD(nt::HKCU, registry_path.c_str(),
+                                 kChromeStatsSampleKey, &out_value) &&
+          out_value == 1);

[Alexei Svitkine (slow), 2016/08/10 21:49:33]

What happens if the registry key isn't set? Would this return "not in sample" -
which seems not correct.

[jwd, 2016/08/11 21:41:02]

Done.

+}
+
 // Returns true if the |source| string matches the |pattern|. The pattern
 // may contain wildcards like '?' which matches one character or a '*'
 // which matches 0 or more characters.
@@ -412,6 +426,10 @@ bool GetCollectStatsConsentForTesting(const std::wstring& exe_path) {
   return GetCollectStatsConsentImpl(exe_path);
 }
 
+bool GetCollectStatsInSample() {
+  return GetCollectStatsInSampleImpl(GetCurrentProcessExePath());
+}
+
 bool ReportingIsEnforcedByPolicy(bool* metrics_is_enforced_by_policy) {
   DWORD value = 0;