Removing iPad Tab Switcher experimental flag.

ios/chrome/browser/snapshots/snapshot_cache_internal.h

 // Copyright 2016 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 IOS_CHROME_BROWSER_SNAPSHOTS_SNAPSHOT_CACHE_INTERNAL_H_
 #define IOS_CHROME_BROWSER_SNAPSHOTS_SNAPSHOT_CACHE_INTERNAL_H_
 
 #import "ios/chrome/browser/snapshots/snapshot_cache_internal.h"
 
 namespace base {
 class FilePath;
 }
 
 @class NSString;
 
 @interface SnapshotCache (Internal)
 // Returns filepath to the color snapshot of |sessionID|.
 + (base::FilePath)imagePathForSessionID:(NSString*)sessionID;
 // Returns filepath to the greyscale snapshot of |sessionID|.
 + (base::FilePath)greyImagePathForSessionID:(NSString*)sessionID;
 // Returns whether the snapshots are cached in a LRU cache.
 - (BOOL)usesLRUCache;
-// Returns whether the in-memory cache (as opposed to the on-disk cache) is
-// enabled.
-- (BOOL)inMemoryCacheIsEnabled;
 @end
 
 #endif  // IOS_CHROME_BROWSER_SNAPSHOTS_SNAPSHOT_CACHE_INTERNAL_H_