Remove instant confirmation dialog that is displayed the first time the instant checkbox is clicked.

chrome/common/pref_names.h

 // Copyright (c) 2012 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_
 
 #include <stddef.h>
@@ skipping 171 matching lines @@
 extern const char kDnsPrefetchingStartupList[];
 extern const char kDnsHostReferralList[];  // OBSOLETE
 extern const char kDnsPrefetchingHostReferralList[];
 extern const char kDisableSpdy[];
 extern const char kHttpServerProperties[];
 extern const char kSpdyServers[];
 extern const char kAlternateProtocolServers[];
 extern const char kDisabledSchemes[];
 extern const char kUrlBlacklist[];
 extern const char kUrlWhitelist[];
-extern const char kInstantConfirmDialogShown[];
 extern const char kInstantEnabled[];
 extern const char kInstantExtendedEnabled[];
 extern const char kInstantUIZeroSuggestUrlPrefix[];
 extern const char kMultipleProfilePrefMigration[];
 extern const char kNetworkPredictionEnabled[];
 extern const char kDefaultAppsInstallState[];
 extern const char kHideWebStoreIcon[];
 #if defined(OS_CHROMEOS)
 extern const char kAudioMute[];
 extern const char kAudioVolumePercent[];
@@ skipping 690 matching lines @@
 extern const char kAppListProfile[];
 
 extern const char kLastAppListLaunchPing[];
 extern const char kAppListLaunchCount[];
 extern const char kLastAppListAppLaunchPing[];
 extern const char kAppListAppLaunchCount[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_