Switch Google Now Background Toggle to use Experiment Variations

chrome/browser/resources/google_now/background.js

Index: chrome/browser/resources/google_now/background.js
diff --git a/chrome/browser/resources/google_now/background.js b/chrome/browser/resources/google_now/background.js
index fdeee8ca3b63bc48b0330017360cd6cc5836da9c..0c3882adebcb29c3f86663ec1bb13ea113c292fe 100644
--- a/chrome/browser/resources/google_now/background.js
+++ b/chrome/browser/resources/google_now/background.js
@@ -118,7 +118,6 @@ var tasks = buildTaskManager(areTasksConflicting);
 
 // Add error processing to API calls.
 tasks.instrumentChromeApiFunction('location.onLocationUpdate.addListener', 0);
-tasks.instrumentChromeApiFunction('metricsPrivate.getFieldTrial', 1);
 tasks.instrumentChromeApiFunction('metricsPrivate.getVariationParams', 1);
 tasks.instrumentChromeApiFunction('notifications.create', 2);
 tasks.instrumentChromeApiFunction('notifications.update', 2);
@@ -868,11 +867,11 @@ function onStateChange() {
     tasks.debugSetStepName('onStateChange-isSignedIn');
     authenticationManager.isSignedIn(function(token) {
       var signedIn = !!token && !!NOTIFICATION_CARDS_URL;
-      instrumented.metricsPrivate.getFieldTrial(
+      instrumented.metricsPrivate.getVariationParams(
           'GoogleNow',
           function(response) {
-            console.log('Experiment Status: ' + response);
-            var enableBackground = (response != 'EnableWithoutBackground');
+            var enableBackground =
+                (response && (response.enableBackground != 'false'));

[vadimt, 2013/08/13 21:05:15]

!response || response.enableBackground != 'false'.

We want background to be the default.

[robliao, 2013/08/13 21:09:15]

That's a bit more permissive than I was expecting.

Which experiments will not include a variation param but still enable Google
Now?

If there's no response, we should treat it as an error, and not enable
background.

On 2013/08/13 21:05:15, vadimt wrote:

[vadimt, 2013/08/13 21:17:10]

Background is a "normal" behavior, and the absence of thereof is an anomaly that
we introduce to compare it with the normal behavior. If in doubt, it's better to
choose the normal behavior.

This is also a step towards being able to delete the experiment after it's not
needed anymore without having to wait till new Chrome build.

[robliao, 2013/08/13 21:30:32]

Done.

             tasks.debugSetStepName(
                 'onStateChange-get-googleGeolocationAccessEnabledPref');
             instrumented.