[ios] Remove old LRU Snapshot Cache flag

Bug: 751553
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: Iaa724ae915ccb81347a7f82c41de47f64697eeee
Reviewed-on: https://chromium-review.googlesource.com/c/1257791Reviewed-by: edchin <edchin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596249}

ios/chrome/browser/experimental_flags.h

@@ -39,9 +39,6 @@ std::string GetOriginServerHost();
 // If |WHATS_NEW_DEFAULT| is returned, no promo is force enabled.
 WhatsNewPromoStatus GetWhatsNewPromoStatus();
 
-// Whether the lru snapshot cache experiment is enabled.
-bool IsLRUSnapshotCacheEnabled();
-
 // Whether memory debugging tools are enabled.
 bool IsMemoryDebuggingEnabled();
 

ios/chrome/browser/experimental_flags.mm

@@ -80,11 +80,6 @@ WhatsNewPromoStatus GetWhatsNewPromoStatus() {
   return static_cast<WhatsNewPromoStatus>(status);
 }
 
-bool IsLRUSnapshotCacheEnabled() {
-  // TODO(crbug.com/751553): Remove this function and its associated code.
-  return NO;
-}
-
 bool IsMemoryDebuggingEnabled() {
 // Always return true for Chromium builds, but check the user default for
 // official builds because memory debugging should never be enabled on stable.