[Media Router] Add UMA histograms tracking component extension version/wakeups

chrome/browser/media/router/media_router_metrics.cc

Index: chrome/browser/media/router/media_router_metrics.cc
diff --git a/chrome/browser/media/router/media_router_metrics.cc b/chrome/browser/media/router/media_router_metrics.cc
index cda93c8ee399e6496c6acc6dec6cc25fdb67e213..8d0ef0041b84e9c719239ffbd229e7d5b8fa97df 100644
--- a/chrome/browser/media/router/media_router_metrics.cc
+++ b/chrome/browser/media/router/media_router_metrics.cc
@@ -6,13 +6,16 @@
 
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/version.h"
+#include "components/version_info/version_info.h"
+#include "extensions/common/extension.h"
 
 namespace media_router {
 
 // static
 void MediaRouterMetrics::RecordMediaRouterDialogOrigin(
     MediaRouterDialogOpenOrigin origin) {
-  DCHECK_NE(static_cast<int>(origin),
+  DCHECK_LT(static_cast<int>(origin),
             static_cast<int>(MediaRouterDialogOpenOrigin::TOTAL_COUNT));
   UMA_HISTOGRAM_ENUMERATION(
       "MediaRouter.Icon.Click.Location", static_cast<int>(origin),
@@ -22,7 +25,7 @@ void MediaRouterMetrics::RecordMediaRouterDialogOrigin(
 // static
 void MediaRouterMetrics::RecordMediaRouteProviderWakeReason(
     MediaRouteProviderWakeReason reason) {
-  DCHECK_NE(static_cast<int>(reason),
+  DCHECK_LT(static_cast<int>(reason),
             static_cast<int>(MediaRouteProviderWakeReason::TOTAL_COUNT));
   UMA_HISTOGRAM_ENUMERATION(
       "MediaRouter.Provider.WakeReason", static_cast<int>(reason),
@@ -46,7 +49,7 @@ void MediaRouterMetrics::RecordMediaRouterDialogLoaded(
 // static
 void MediaRouterMetrics::RecordMediaRouterInitialUserAction(
     MediaRouterUserAction action) {
-  DCHECK_NE(static_cast<int>(action),
+  DCHECK_LT(static_cast<int>(action),
             static_cast<int>(MediaRouterUserAction::TOTAL_COUNT));
   UMA_HISTOGRAM_ENUMERATION(
       "MediaRouter.Ui.FirstAction", static_cast<int>(action),
@@ -56,12 +59,61 @@ void MediaRouterMetrics::RecordMediaRouterInitialUserAction(
 // static
 void MediaRouterMetrics::RecordRouteCreationOutcome(
     MediaRouterRouteCreationOutcome outcome) {
-  DCHECK_NE(static_cast<int>(outcome),
-            static_cast<int>(
-                MediaRouterRouteCreationOutcome::TOTAL_COUNT));
+  DCHECK_LT(static_cast<int>(outcome),
+            static_cast<int>(MediaRouterRouteCreationOutcome::TOTAL_COUNT));
   UMA_HISTOGRAM_ENUMERATION(
     "MediaRouter.Route.CreationOutcome", static_cast<int>(outcome),
     static_cast<int>(MediaRouterRouteCreationOutcome::TOTAL_COUNT));
 }
 
+// static
+void MediaRouterMetrics::RecordMediaRouteProviderVersion(
+    const extensions::Extension& extension) {
+  MediaRouteProviderVersion version = MediaRouteProviderVersion::UNKNOWN;
+  const base::Version* extension_version = extension.version();
+  if (extension_version) {
+    version = GetMediaRouteProviderVersion(
+        *extension_version, base::Version(version_info::GetVersionNumber()));
+  }
+
+  DCHECK_LT(static_cast<int>(version),
+            static_cast<int>(MediaRouteProviderVersion::TOTAL_COUNT));
+  UMA_HISTOGRAM_ENUMERATION(
+      "MediaRouter.Provider.Version", static_cast<int>(version),
+      static_cast<int>(MediaRouteProviderVersion::TOTAL_COUNT));
+}
+
+// static
+void MediaRouterMetrics::RecordMediaRouteProviderWakeup(
+    MediaRouteProviderWakeup wakeup) {
+  DCHECK_LT(static_cast<int>(wakeup),
+            static_cast<int>(MediaRouteProviderWakeup::TOTAL_COUNT));
+  UMA_HISTOGRAM_ENUMERATION(
+      "MediaRouter.Provider.Wakeup", static_cast<int>(wakeup),
+      static_cast<int>(MediaRouteProviderWakeup::TOTAL_COUNT));
+}
+
+// static
+MediaRouteProviderVersion MediaRouterMetrics::GetMediaRouteProviderVersion(
+    const base::Version& extension_version,
+    const base::Version& browser_version) {
+  if (!extension_version.IsValid() || !extension_version.components().size() ||

[Wez, 2016/03/18 23:32:00]

nit: Use empty() instead of !size().

[mark a. foltz, 2016/03/19 00:15:02]

Done.

+      !browser_version.IsValid() || !browser_version.components().size()) {
+    return MediaRouteProviderVersion::UNKNOWN;
+  }
+
+  uint32_t extension_major = extension_version.components()[0];
+  uint32_t browser_major = browser_version.components()[0];
+  // Sanity check.
+  if (extension_major == 0 || browser_major == 0) {

[Wez, 2016/03/18 23:32:00]

nit: Hard to imagine when |browser_major| could be zero, since this code will
only run in official Chrome builds; want to DCHECK it here as well?

[mark a. foltz, 2016/03/19 00:15:02]

That seems a little drastic for this since it's just metrics.  A better place
for the check would behind an #ifdef in version_info.cc which is stamped with
the version string.
  

+    return MediaRouteProviderVersion::UNKNOWN;
+  } else if (extension_major >= browser_major) {
+    return MediaRouteProviderVersion::SAME_VERSION_AS_CHROME;
+  } else if (browser_major - extension_major == 1) {
+    return MediaRouteProviderVersion::ONE_VERSION_BEHIND_CHROME;
+  } else {
+    return MediaRouteProviderVersion::MULTIPLE_VERSIONS_BEHIND_CHROME;
+  }
+}
+
 }  // namespace media_router