Add UMA to hotword trigger extension.

chrome/browser/resources/hotword/state_manager.js

Index: chrome/browser/resources/hotword/state_manager.js
diff --git a/chrome/browser/resources/hotword/state_manager.js b/chrome/browser/resources/hotword/state_manager.js
index f71755d3cb4f7d28fd375b35afc46a88b3c75654..f378fdab475e2f8e5626385b46d580a147a5cf8a 100644
--- a/chrome/browser/resources/hotword/state_manager.js
+++ b/chrome/browser/resources/hotword/state_manager.js
@@ -102,6 +102,34 @@ cr.define('hotword', function() {
   };
   var State_ = StateManager.State_;
 
+  var UmaMediaStreamOpenResults_ = {
+    // These first error are defined by the MediaStream spec:
+    // http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-MediaStreamError
+    'NotSupportedError':
+        hotword.constants.UmaMediaStreamOpenResult.NOT_SUPPORTED,
+    'PermissionDeniedError':
+        hotword.constants.UmaMediaStreamOpenResult.PERMISSION_DENIED,
+    'ConstraintNotSatisfiedError':
+        hotword.constants.UmaMediaStreamOpenResult.CONSTRAINT_NOT_SATISFIED,
+    'OverconstrainedError':
+        hotword.constants.UmaMediaStreamOpenResult.OVERCONSTRAINED,
+    'NotFoundError': hotword.constants.UmaMediaStreamOpenResult.NOT_FOUND,
+    'AbortError': hotword.constants.UmaMediaStreamOpenResult.ABORT,
+    'SourceUnavailableError':
+        hotword.constants.UmaMediaStreamOpenResult.SOURCE_UNAVAILABLE,
+    // The next few errors are chrome-specific. See:
+    // content/renderer/media/user_media_client_impl.cc
+    // (UserMediaClientImpl::GetUserMediaRequestFailed)
+    'PermissionDismissedError':
+        hotword.constants.UmaMediaStreamOpenResult.PERMISSION_DISMISSED,
+    'InvalidStateError':
+        hotword.constants.UmaMediaStreamOpenResult.INVALID_STATE,
+    'DevicesNotFoundError':
+        hotword.constants.UmaMediaStreamOpenResult.DEVICES_NOT_FOUND,
+    'InvalidSecurityOriginError':
+        hotword.constants.UmaMediaStreamOpenResult.INVALID_SECURITY_ORIGIN
+  };
+
   StateManager.prototype = {
     /**
      * Request status details update. Intended to be called from the
@@ -199,12 +227,26 @@ cr.define('hotword', function() {
           navigator.webkitGetUserMedia(
               /** @type {MediaStreamConstraints} */ (constraints),
               function(stream) {
+                hotword.metrics.recordEnum(

[rpetterson, 2014/10/23 19:03:36]

I don't fully understand when function(stream) vs function(error) gets called.
Is it possible both could be called?

[Anand Mistry (off Chromium), 2014/10/23 21:38:16]

It's one or the other, never both.
function(stream) is called when the requested stream (audio in our case) is
successfully opened.
function(error) is called on any fatal error condition, such as resource busy,
or no device available.

+                    hotword.constants.UmaMetrics.MEDIA_STREAM_RESULT,
+                    hotword.constants.UmaMediaStreamOpenResult.SUCCESS,
+                    hotword.constants.UmaMediaStreamOpenResult.MAX);
                 if (!this.pluginManager_.initialize(naclArch, stream)) {
                   this.state_ = State_.ERROR;
                   this.shutdownPluginManager_();
                 }
               }.bind(this),
               function(error) {
+                if (error.name in UmaMediaStreamOpenResults_) {
+                  var metricValue = UmaMediaStreamOpenResults_[error.name];
+                } else {
+                  var metricValue =
+                      hotword.constants.UmaMediaStreamOpenResult.UNKNOWN;
+                }
+                hotword.metrics.recordEnum(
+                    hotword.constants.UmaMetrics.MEDIA_STREAM_RESULT,
+                    metricValue,
+                    hotword.constants.UmaMediaStreamOpenResult.MAX);
                 this.state_ = State_.ERROR;
                 this.pluginManager_ = null;
               }.bind(this));
@@ -285,6 +327,8 @@ cr.define('hotword', function() {
      */
     onTrigger_: function() {
       hotword.debug('Hotword triggered!');
+      chrome.metricsPrivate.recordUserAction(
+          hotword.constants.UmaMetrics.TRIGGER);
       assert(this.pluginManager_, 'No NaCl plugin loaded on trigger');
       // Detector implicitly stops when the hotword is detected.
       this.state_ = State_.STOPPED;