Check whether the plugin is disabled in OnIsInternalPluginRegisteredForMimeType().

chrome/browser/plugins/plugin_info_message_filter.cc

Index: chrome/browser/plugins/plugin_info_message_filter.cc
diff --git a/chrome/browser/plugins/plugin_info_message_filter.cc b/chrome/browser/plugins/plugin_info_message_filter.cc
index 634e4bc6dfde697fc60249ae0e4e95af09e57b26..cad51f0d2bea0e3968adc1d4f026151f4fa7e356 100644
--- a/chrome/browser/plugins/plugin_info_message_filter.cc
+++ b/chrome/browser/plugins/plugin_info_message_filter.cc
@@ -170,6 +170,24 @@ void PluginInfoMessageFilter::PluginsLoaded(
 }
 
 #if defined(ENABLE_PEPPER_CDMS)
+
+enum PluginRegistrationStatusForUMA {
+  PLUGIN_REGISTERED,
+  PLUGIN_NOT_REGISTERED,
+  PLUGIN_DISABLED,
+  PLUGIN_REGISTRATION_STATUS_MAX
+};
+
+static void SendPluginRegistrationUMA(const std::string& mime_type,
+                                      PluginRegistrationStatusForUMA status) {
+  // Only report results for Widevine CDM.

[ddorwin, 2014/07/18 23:50:18]

#if defined(WIDEVINE_CDM_AVAILABLE) && defined(ENABLE_PEPPER_CDMS)

[xhwang, 2014/07/19 00:07:14]

Done.

+  if (mime_type != kWidevineCdmPluginMimeType)
+    return;
+
+  UMA_HISTOGRAM_ENUMERATION("Plugin.RegistrationStatus.WidevineCdm",
+                            status, PLUGIN_REGISTRATION_STATUS_MAX);
+}
+
 void PluginInfoMessageFilter::OnIsInternalPluginRegisteredForMimeType(
     const std::string& mime_type,
     bool* is_registered,
@@ -177,22 +195,33 @@ void PluginInfoMessageFilter::OnIsInternalPluginRegisteredForMimeType(
     std::vector<base::string16>* additional_param_values) {
   std::vector<WebPluginInfo> plugins;
   PluginService::GetInstance()->GetInternalPlugins(&plugins);
+
+  bool is_plugin_disabled = false;
   for (size_t i = 0; i < plugins.size(); ++i) {
     const std::vector<content::WebPluginMimeType>& mime_types =
         plugins[i].mime_types;
     for (size_t j = 0; j < mime_types.size(); ++j) {
       if (mime_types[j].mime_type == mime_type) {
+        if (!context_.IsPluginEnabled(plugins[i])) {

[ddorwin, 2014/07/18 23:50:18]

nit: With all the nesting and complexity, maybe we should have a local var for
"plugin".

[xhwang, 2014/07/19 00:07:14]

Done.

+          is_plugin_disabled = true;
+          break;
+        }
+
         *is_registered = true;
         *additional_param_names = mime_types[j].additional_param_names;
         *additional_param_values = mime_types[j].additional_param_values;
+        SendPluginRegistrationUMA(mime_type, PLUGIN_REGISTERED);
         return;
       }
     }
   }
 
   *is_registered = false;
+  SendPluginRegistrationUMA(
+      mime_type, is_plugin_disabled ? PLUGIN_DISABLED : PLUGIN_NOT_REGISTERED);

[ddorwin, 2014/07/18 23:50:18]

For the record, PLUGIN_DISABLED will not be sent if there happened to be another
plugin registered for this mime type that was not disabled. (No action
required.)

[xhwang, 2014/07/19 00:07:13]

Acknowledged.

 }
-#endif
+
+#endif // defined(ENABLE_PEPPER_CDMS)
 
 void PluginInfoMessageFilter::Context::DecidePluginStatus(
     const GetPluginInfo_Params& params,
@@ -403,3 +432,7 @@ void PluginInfoMessageFilter::Context::MaybeGrantAccess(
   }
 }
 
+bool PluginInfoMessageFilter::Context::IsPluginEnabled(
+    const content::WebPluginInfo& plugin) const {
+  return plugin_prefs_->IsPluginEnabled(plugin);
+}