The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5104459f52c44caa94a5550e51bb3d29bcd4ec01

commit 5104459f52c44caa94a5550e51bb3d29bcd4ec01
Author: Sylvain Defresne <sdefresne@chromium.org>
Date: Tue May 30 14:52:16 2017

[ios] Remove SnapshotCache -useLRUCache method.

The experiment is over and the LRU cache is always used, remove the
method -useLRUCache and the old code path (using a NSDictionary).

Fix improper uses of abbreviation when naming variables ("img" used
for "image" which is against the style guide).

BUG= 687904 

Change-Id: Ideab521b1c1f541e344e0ca5f398adc685a83b3d
Reviewed-on: https://chromium-review.googlesource.com/517498
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#475523}
[modify] https://crrev.com/5104459f52c44caa94a5550e51bb3d29bcd4ec01/ios/chrome/browser/snapshots/snapshot_cache.mm
[modify] https://crrev.com/5104459f52c44caa94a5550e51bb3d29bcd4ec01/ios/chrome/browser/snapshots/snapshot_cache_internal.h
[modify] https://crrev.com/5104459f52c44caa94a5550e51bb3d29bcd4ec01/ios/chrome/browser/snapshots/snapshot_cache_unittest.mm