[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..54ef591102d61c8df59475972c3b7e2325cdc3b4 100644
--- a/chrome/browser/media/router/media_router_metrics.cc
+++ b/chrome/browser/media/router/media_router_metrics.cc
@@ -4,8 +4,13 @@
 
 #include "chrome/browser/media/router/media_router_metrics.h"
 
+#include <limits.h>
+
 #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 {
 
@@ -64,4 +69,70 @@ void MediaRouterMetrics::RecordRouteCreationOutcome(
     static_cast<int>(MediaRouterRouteCreationOutcome::TOTAL_COUNT));
 }
 
+// static
+void MediaRouterMetrics::RecordMediaRouteProviderVersion(
+    const extensions::Extension& extension) {
+  const base::Version* extension_version = extension.version();
+  if (!extension_version) {
+    MediaRouterMetrics::RecordMediaRouteProviderVersion(
+        MediaRouteProviderVersion::UNKNOWN);
+    return;
+  }
+
+  base::Version browser_version(version_info::GetVersionNumber());
+  int version_difference =
+      GetVersionDifference(*extension_version, browser_version);
+  if (version_difference == std::numeric_limits<int>::min()) {
+    // Extension installed, version is invalid.
+    MediaRouterMetrics::RecordMediaRouteProviderVersion(
+        MediaRouteProviderVersion::UNKNOWN);
+  } else if (version_difference >= 0) {
+    MediaRouterMetrics::RecordMediaRouteProviderVersion(
+        MediaRouteProviderVersion::SAME_VERSION);
+  } else if (version_difference == -1) {
+    MediaRouterMetrics::RecordMediaRouteProviderVersion(
+        MediaRouteProviderVersion::PREVIOUS_VERSION);
+  } else {
+    MediaRouterMetrics::RecordMediaRouteProviderVersion(
+        MediaRouteProviderVersion::OUT_OF_DATE_VERSION);
+  }
+}
+
+// static
+void MediaRouterMetrics::RecordMediaRouteProviderVersion(
+    MediaRouteProviderVersion version) {
+  DCHECK_NE(static_cast<int>(version),

[Ilya Sherman, 2016/03/16 22:23:05]

Optional nit: Maybe DCHECK_LT?  Ditto below.

+            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_NE(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
+int MediaRouterMetrics::GetVersionDifference(const base::Version& first,
+                                             const base::Version& second) {
+  if (!first.IsValid() || !first.components().size() || !second.IsValid() ||
+      !second.components().size()) {
+    return std::numeric_limits<int>::min();
+  }
+
+  uint32_t first_major = first.components()[0];
+  uint32_t second_major = second.components()[0];
+  // Sanity check.
+  if (first_major < 1 || second_major < 1)
+    return std::numeric_limits<int>::min();
+
+  return first_major - second_major;
+}
+
 }  // namespace media_router