Removing iPad Tab Switcher experimental flag.

ios/chrome/browser/snapshots/snapshot_cache.mm

 // Copyright 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.
 
 #import "ios/chrome/browser/snapshots/snapshot_cache.h"
 
 #import <UIKit/UIKit.h>
 
 #include "base/critical_closure.h"
 #include "base/files/file_enumerator.h"
@@ skipping 214 matching lines @@
   }
   // Cap snapshot resolution to 2x to reduce the amount of memory they use.
   return MIN([UIScreen mainScreen].scale, 2.0);
 }
 
 - (void)retrieveImageForSessionID:(NSString*)sessionID
                          callback:(void (^)(UIImage*))callback {
   DCHECK_CURRENTLY_ON(web::WebThread::UI);
   DCHECK(sessionID);
 
-  if (![self inMemoryCacheIsEnabled] && !callback)
-    return;
-
   UIImage* img = nil;
   if (lruCache_)
     img = [lruCache_ objectForKey:sessionID];
   else
     img = [imageDictionary_ objectForKey:sessionID];
 
   if (img) {
     if (callback)
       callback(img);
     return;
   }
 
   base::PostTaskAndReplyWithResult(
       web::WebThread::GetTaskRunnerForThread(web::WebThread::FILE_USER_BLOCKING)
           .get(),
       FROM_HERE, base::BindBlock(^base::scoped_nsobject<UIImage>() {
         // Retrieve the image on a high priority thread.
         return base::scoped_nsobject<UIImage>([ReadImageFromDisk(
             [SnapshotCache imagePathForSessionID:sessionID]) retain]);
       }),
       base::BindBlock(^(base::scoped_nsobject<UIImage> image) {
-        if ([self inMemoryCacheIsEnabled] && image) {
+        if (image) {
           if (lruCache_)
             [lruCache_ setObject:image forKey:sessionID];
           else
             [imageDictionary_ setObject:image forKey:sessionID];
         }
         if (callback)
           callback(image);
       }));
 }
 
 - (void)setImage:(UIImage*)img withSessionID:(NSString*)sessionID {
   DCHECK_CURRENTLY_ON(web::WebThread::UI);
   if (!img || !sessionID)
     return;
 
-  if ([self inMemoryCacheIsEnabled]) {
-    if (lruCache_)
-      [lruCache_ setObject:img forKey:sessionID];
-    else
-      [imageDictionary_ setObject:img forKey:sessionID];
-  }
+  if (lruCache_)
+    [lruCache_ setObject:img forKey:sessionID];
+  else
+    [imageDictionary_ setObject:img forKey:sessionID];
+
   // Save the image to disk.
   web::WebThread::PostBlockingPoolSequencedTask(
       kSequenceToken, FROM_HERE,
       base::BindBlock(^{
         base::scoped_nsobject<UIImage> image([img retain]);
         WriteImageToDisk(image,
                          [SnapshotCache imagePathForSessionID:sessionID]);
       }));
 }
 
@@ skipping 105 matching lines @@
     return;
   backgroundingImageSessionId_.reset([sessionID copy]);
   if (lruCache_) {
     backgroundingColorImage_.reset([[lruCache_ objectForKey:sessionID] retain]);
   } else {
     backgroundingColorImage_.reset(
         [[imageDictionary_ objectForKey:sessionID] retain]);
   }
 }
 
-- (BOOL)inMemoryCacheIsEnabled {
-  // In-memory cache on iPad is enabled only when the tab switcher is enabled.
-  return !IsIPadIdiom() || experimental_flags::IsTabSwitcherEnabled();
-}
-
 - (BOOL)usesLRUCache {
-  // Always use the LRUCache when the tab switcher is enabled.
-  return experimental_flags::IsTabSwitcherEnabled() ||
-         experimental_flags::IsLRUSnapshotCacheEnabled();
+  // TODO(crbug.com/687904): Remove the non-LRU cache code.
+  return true;
 }
 
 - (void)handleLowMemory {
   DCHECK_CURRENTLY_ON(web::WebThread::UI);
   base::scoped_nsobject<NSMutableDictionary> dictionary(
       [[NSMutableDictionary alloc] initWithCapacity:2]);
   for (NSString* sessionID in pinnedIDs_) {
     UIImage* image = nil;
     if (lruCache_)
       image = [lruCache_ objectForKey:sessionID];
@@ skipping 177 matching lines @@
 
 - (BOOL)hasGreyImageInMemory:(NSString*)sessionID {
   return [greyImageDictionary_ objectForKey:sessionID] != nil;
 }
 
 - (NSUInteger)lruCacheMaxSize {
   return [lruCache_ maxCacheSize];
 }
 
 @end