Restrict Instant field trial to UMA opt-in users.

chrome/common/pref_names.h

 // Copyright (c) 2011 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.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 #pragma once
 
@@ skipping 77 matching lines @@
 extern const char kDnsStartupPrefetchList[];  // OBSOLETE
 extern const char kDnsPrefetchingStartupList[];
 extern const char kDnsHostReferralList[];  // OBSOLETE
 extern const char kDnsPrefetchingHostReferralList[];
 extern const char kDisableSpdy[];
 extern const char kDisabledSchemes[];
 extern const char kInstantConfirmDialogShown[];
 extern const char kInstantEnabled[];
 extern const char kInstantEnabledOnce[];
 extern const char kInstantEnabledTime[];
-extern const char kInstantFieldTrialRandomDraw[];
 extern const char kInstantPromo[];
 extern const char kMultipleProfilePrefMigration[];
 extern const char kNetworkPredictionEnabled[];
 #if defined(OS_CHROMEOS)
 extern const char kAudioMute[];
 extern const char kAudioVolume[];
 extern const char kTapToClickEnabled[];
 extern const char kTouchpadSensitivity[];
 extern const char kUse24HourClock[];
 extern const char kLanguageCurrentInputMethod[];
@@ skipping 420 matching lines @@
 extern const char kCustomHandlersEnabled[];
 
 extern const char kUserCreatedLoginItem[];
 extern const char kBackgroundModeEnabled[];
 
 extern const char kDevicePolicyRefreshRate[];
 extern const char kUserPolicyRefreshRate[];
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_