Add more histograms to track Instant and Field Trial state.

+ Makes the "OptOut" histogram more useful, by also counting enables
  (previously, we just had the raw number of opt-outs, with no information
  about the denominator, and thus, the rate of opt-outs).
+ Adds a histogram to track the various reasons for assigning a field trial
  group. This is motivated by @mpearson's analysis that shows large
  discrepancies between what we expect and what we actually see in the current
  histogram data.

BUG=none
TEST=none


Review URL: http://codereview.chromium.org/9958031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@130013 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 9 insertions, 4 deletions

diff --git a/chrome/browser/instant/instant_controller.cc b/chrome/browser/instant/instant_controller.cc
index 0d31d4a..b1d6e3f 100644
--- a/chrome/browser/instant/instant_controller.cc
+++ b/chrome/browser/instant/instant_controller.cc
@@ -113,6 +113,11 @@ void InstantController::Enable(Profile* profile) {
   if (!service)
     return;
 
+  base::Histogram* histogram = base::LinearHistogram::FactoryGet(
+      "Instant.Preference" + InstantFieldTrial::GetGroupName(profile), 1, 2, 3,
+      base::Histogram::kUmaTargetedHistogramFlag);
+  histogram->Add(1);
+
   service->SetBoolean(prefs::kInstantEnabledOnce, true);
   service->SetBoolean(prefs::kInstantEnabled, true);
   service->SetBoolean(prefs::kInstantConfirmDialogShown, true);
@@ -135,10 +140,10 @@ void InstantController::Disable(Profile* profile) {
                                 delta.InMinutes(), 1, 60 * 24 * 10, 50);
   }
 
-  base::Histogram* histogram = base::Histogram::FactoryGet(
-      "Instant.OptOut" + InstantFieldTrial::GetGroupName(profile), 1, 1000000,
-      50, base::Histogram::kUmaTargetedHistogramFlag);
-  histogram->Add(1);
+  base::Histogram* histogram = base::LinearHistogram::FactoryGet(
+      "Instant.Preference" + InstantFieldTrial::GetGroupName(profile), 1, 2, 3,
+      base::Histogram::kUmaTargetedHistogramFlag);
+  histogram->Add(0);
 
   service->SetBoolean(prefs::kInstantEnabledOnce, true);
   service->SetBoolean(prefs::kInstantEnabled, false);