[Extensions] Add a field trial for reporting abuse on uninstall

chrome/browser/extensions/extension_uninstall_dialog.cc

Index: chrome/browser/extensions/extension_uninstall_dialog.cc
diff --git a/chrome/browser/extensions/extension_uninstall_dialog.cc b/chrome/browser/extensions/extension_uninstall_dialog.cc
index 01bc7cda9f34eef1988616464f1b10d44b36d2ae..5bdf96fdefc5a29263bbaaa310e4e4416442b614 100644
--- a/chrome/browser/extensions/extension_uninstall_dialog.cc
+++ b/chrome/browser/extensions/extension_uninstall_dialog.cc
@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/field_trial.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile.h"
@@ -128,9 +129,20 @@ std::string ExtensionUninstallDialog::GetHeadingText() {
 }
 
 bool ExtensionUninstallDialog::ShouldShowReportAbuseCheckbox() const {
-  // TODO(devlin): Add a field trial for reporting abuse on uninstallation.
-  // See crbug.com/441377.
-  return false;
+  static const char kExperimentName[] = "ExtensionUninstall.ReportAbuse";
+  static const char kControlGroupName[] = "Control";
+  static const char kShowCheckboxGroup[] = "ShowCheckbox";
+  // TODO(devlin): Turn on this field trial. See crbug.com/441377.
+  scoped_refptr<base::FieldTrial> trial(
+      base::FieldTrialList::FactoryGetFieldTrial(
+          kExperimentName,
+          100,  // Total probability.
+          kControlGroupName,

[Finnur, 2015/03/23 11:08:55]

It is unusual to see a control group named here. Usually people put "Disabled"
or "Default" here. Also, are you sure a control group is not created explicitly
for you (because then you'd have two, right?)

This may be perfectly fine. Just wanted to mention it.

[Devlin, 2015/03/23 15:43:23]

I figured that the default would be the control (since right now they are
synonymous - no checkbox), but maybe it makes more sense to call it "Default" in
case this changes.  (Of course, if it changes, we may then need to add a real
control group.)

+          2015, 7, 31,  // End date.
+          base::FieldTrial::ONE_TIME_RANDOMIZED,
+          nullptr));
+  int experiment_group = trial->AppendGroup(kShowCheckboxGroup, 0);

[Finnur, 2015/03/23 11:08:55]

Don't you want this to be > 0 and remove the TODO? 

[Devlin, 2015/03/23 15:43:23]

Not quite yet - we're still waiting on UI feedback and exact numbers.  Just
instrumenting all this so that it should (hopefully) be a simple "Turn it on"
patch. :)

+  return base::FieldTrialList::FindValue(kExperimentName) == experiment_group;
 }
 
 void ExtensionUninstallDialog::HandleReportAbuse() {