Merge 212950 "Add an experiment for showing the new tab button i..."

> Add an experiment for showing the new tab button in the mobile toolbar.
> 
> Creates a utility class to access field trial information in Java.
> 
> BUG=226870
> 
> Review URL: https://chromiumcodereview.appspot.com/18938003

TBR=tedchoc@chromium.org

Review URL: https://codereview.chromium.org/20784003

git-svn-id: svn://svn.chromium.org/chrome/branches/1547/src@214007 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 124 insertions, 0 deletions

diff --git a/chrome/android/java/src/org/chromium/chrome/browser/FieldTrialHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/FieldTrialHelper.java
new file mode 100644
index 0000000..fbacd26
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/FieldTrialHelper.java
@@ -0,0 +1,24 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser;
+
+/**
+ * Helper to get field trial information.
+ */
+public class FieldTrialHelper {
+
+    private FieldTrialHelper() {}
+
+    /**
+     * @param trialName The name of the trial to get the group for.
+     * @return The group name chosen for the named trial, or the empty string if the trial does
+     *         not exist.
+     */
+    public static String getFieldTrialFullName(String trialName) {
+        return nativeGetFieldTrialFullName(trialName);
+    }
+
+    private static native String nativeGetFieldTrialFullName(String trialName);
+}
diff --git a/chrome/browser/android/chrome_jni_registrar.cc b/chrome/browser/android/chrome_jni_registrar.cc
index 7bd9e40..a573c58 100644
--- a/chrome/browser/android/chrome_jni_registrar.cc
+++ b/chrome/browser/android/chrome_jni_registrar.cc
@@ -10,6 +10,7 @@
 #include "chrome/browser/android/chrome_web_contents_delegate_android.h"
 #include "chrome/browser/android/content_view_util.h"
 #include "chrome/browser/android/dev_tools_server.h"
+#include "chrome/browser/android/field_trial_helper.h"
 #include "chrome/browser/android/intent_helper.h"
 #include "chrome/browser/android/provider/chrome_browser_provider.h"
 #include "chrome/browser/android/tab_android.h"
@@ -59,6 +60,7 @@ static base::android::RegistrationMethod kChromeRegisteredMethods[] = {
     RegisterChromeWebContentsDelegateAndroid },
   { "ContentViewUtil", RegisterContentViewUtil },
   { "DevToolsServer", RegisterDevToolsServer },
+  { "FieldTrialHelper", RegisterFieldTrialHelper },
   { "IntentHelper", RegisterIntentHelper },
   { "JavascriptAppModalDialog",
     JavascriptAppModalDialogAndroid::RegisterJavascriptAppModalDialog },
diff --git a/chrome/browser/android/field_trial_helper.cc b/chrome/browser/android/field_trial_helper.cc
new file mode 100644
index 0000000..b3be6d2
--- /dev/null
+++ b/chrome/browser/android/field_trial_helper.cc
@@ -0,0 +1,33 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/android/field_trial_helper.h"
+
+#include <jni.h>
+
+#include "base/android/jni_string.h"
+#include "base/metrics/field_trial.h"
+#include "jni/FieldTrialHelper_jni.h"
+
+using base::android::ConvertJavaStringToUTF8;
+using base::android::ConvertUTF8ToJavaString;
+
+static jstring GetFieldTrialFullName(JNIEnv* env,
+                                     jclass clazz,
+                                     jstring jtrial_name) {
+  std::string trial_name(ConvertJavaStringToUTF8(env, jtrial_name));
+  return ConvertUTF8ToJavaString(
+      env,
+      base::FieldTrialList::FindFullName(trial_name)).Release();
+}
+
+namespace chrome {
+namespace android {
+
+bool RegisterFieldTrialHelper(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace android
+}  // namespace chrome
diff --git a/chrome/browser/android/field_trial_helper.h b/chrome/browser/android/field_trial_helper.h
new file mode 100644
index 0000000..6f92ac0
--- /dev/null
+++ b/chrome/browser/android/field_trial_helper.h
@@ -0,0 +1,18 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_ANDROID_FIELD_TRIAL_HELPER_H_
+#define CHROME_BROWSER_ANDROID_FIELD_TRIAL_HELPER_H_
+
+#include <jni.h>
+
+namespace chrome {
+namespace android {
+
+bool RegisterFieldTrialHelper(JNIEnv* env);
+
+}  // namespace android
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_ANDROID_FIELD_TRIAL_HELPER_H_
diff --git a/chrome/browser/chrome_browser_field_trials_mobile.cc b/chrome/browser/chrome_browser_field_trials_mobile.cc
index 7fb1896..5e17ca7 100644
--- a/chrome/browser/chrome_browser_field_trials_mobile.cc
+++ b/chrome/browser/chrome_browser_field_trials_mobile.cc
@@ -9,6 +9,7 @@
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/prefs/pref_service.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
 
 namespace chrome {
@@ -51,12 +52,55 @@ void DataCompressionProxyFieldTrial() {
           << ". Selected group id: " << v;
 }
 
+void NewTabButtonInToolbarFieldTrial(const CommandLine& parsed_command_line) {
+  // Do not enable this field trials for tablet devices.
+  if (parsed_command_line.HasSwitch(switches::kTabletUI))
+    return;
+
+  const char kPhoneNewTabToolbarButtonFieldTrialName[] =
+      "PhoneNewTabToolbarButton";
+  const base::FieldTrial::Probability kPhoneNewTabToolbarButtonDivisor = 100;
+
+  // 50/100 = 50% for Non-Stable users.
+  //  0/100 = 0%  for Stable users.
+  const base::FieldTrial::Probability kPhoneNewTabToolbarButtonNonStable = 50;
+  const base::FieldTrial::Probability kPhoneNewTabToolbarButtonStable = 0;
+  const char kEnabled[] = "Enabled";
+  const char kDisabled[] = "Disabled";
+
+  // Find out if this is a stable channel.
+  const bool kIsStableChannel =
+      chrome::VersionInfo::GetChannel() == chrome::VersionInfo::CHANNEL_STABLE;
+
+  // Experiment enabled until Jan 1, 2015. By default, disabled.
+  scoped_refptr<base::FieldTrial> trial(
+      base::FieldTrialList::FactoryGetFieldTrial(
+          kPhoneNewTabToolbarButtonFieldTrialName,
+          kPhoneNewTabToolbarButtonDivisor,
+          kDisabled, 2015, 1, 1, NULL));
+
+  // We want our trial results to be persistent.
+  trial->UseOneTimeRandomization();
+  const int kEnabledGroup = trial->AppendGroup(
+      kEnabled,
+      kIsStableChannel ?
+          kPhoneNewTabToolbarButtonStable : kPhoneNewTabToolbarButtonNonStable);
+
+  const int v = trial->group();
+  VLOG(1) << "Phone NewTab toolbar button enabled group id: " << kEnabledGroup
+          << ". Selected group id: " << v;
+}
+
 }  // namespace
 
 void SetupMobileFieldTrials(const CommandLine& parsed_command_line,
                             const base::Time& install_time,
                             PrefService* local_state) {
   DataCompressionProxyFieldTrial();
+
+#if defined(OS_ANDROID)
+  NewTabButtonInToolbarFieldTrial(parsed_command_line);
+#endif
 }
 
 }  // namespace chrome
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index e0d5a7c..fda4e7f 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -96,6 +96,8 @@
         'browser/android/crash_dump_manager.h',
         'browser/android/dev_tools_server.cc',
         'browser/android/dev_tools_server.h',
+        'browser/android/field_trial_helper.cc',
+        'browser/android/field_trial_helper.h',
         'browser/android/google_location_settings_helper.h',
         'browser/android/infobar_stubs.cc',
         'browser/android/intent_helper.cc',
@@ -3287,6 +3289,7 @@
             'android/java/src/org/chromium/chrome/browser/ContentViewUtil.java',
             'android/java/src/org/chromium/chrome/browser/DevToolsServer.java',
             'android/java/src/org/chromium/chrome/browser/database/SQLiteCursor.java',
+            'android/java/src/org/chromium/chrome/browser/FieldTrialHelper.java',
             'android/java/src/org/chromium/chrome/browser/IntentHelper.java',
             'android/java/src/org/chromium/chrome/browser/JavascriptAppModalDialog.java',
             'android/java/src/org/chromium/chrome/browser/NavigationPopup.java',