Change storage limit of App Cache Memdisk to be automatic.

There has been a mistake in a previous CL aimed to update the max limit
of AppCache Memdisk from fixed size to automatic (crrev.com/c/1771809).
It is updated in this CL.

Bug: 818045
Change-Id: I0a554d3b7a22a46c4e507909e01bc5c38f4c5e07
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1773069Reviewed-by: Ramin Halavati <rhalavati@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Auto-Submit: Ramin Halavati <rhalavati@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690726}

content/browser/appcache/appcache_storage_impl.cc

@@ -1848,9 +1848,8 @@ AppCacheDiskCache* AppCacheStorageImpl::disk_cache() {
     disk_cache_ = std::make_unique<AppCacheDiskCache>();
     if (is_incognito_) {
       rv = disk_cache_->InitWithMemBackend(
-          std::numeric_limits<int>::max(),
-          base::BindOnce(&AppCacheStorageImpl::OnDiskCacheInitialized,
-                         base::Unretained(this)));
+          0, base::BindOnce(&AppCacheStorageImpl::OnDiskCacheInitialized,
+                            base::Unretained(this)));
     } else {
       expecting_cleanup_complete_on_disable_ = true;