Add LargeIconCache and LargeIconServiceFactory for iOS.

ios/chrome/browser/favicon/large_icon_cache.cc

+// Copyright 2015 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.
+
+#include "ios/chrome/browser/favicon/large_icon_cache.h"
+
+#include "components/favicon_base/fallback_icon_style.h"
+#include "components/favicon_base/favicon_types.h"
+#include "url/gurl.h"
+
+namespace {
+
+const int kMaxCacheSize = 12;

[noyau (Ping after 24h), 2015/10/30 23:22:31]

Do you need to cache 12 of them on all platforms? Should this number be smaller
on devices with a smaller form factor?

[justincohen, 2015/10/31 03:54:21]

Right now smaller form factors still load 12 favicons.  Even if they load less,
the cache only fills up if 12 unique GURLs are loaded.

+
+}  // namespace
+
+struct LargeIconCacheEntry {
+  LargeIconCacheEntry() {}
+  ~LargeIconCacheEntry() {}
+
+  scoped_ptr<favicon_base::LargeIconResult> result;
+};
+
+LargeIconCache::LargeIconCache() : cache_(kMaxCacheSize) {}
+
+LargeIconCache::~LargeIconCache() {}
+
+void LargeIconCache::SetCachedResult(
+    const GURL& url,
+    const favicon_base::LargeIconResult& result) {
+  LargeIconCacheEntry* entry = new LargeIconCacheEntry;
+  entry->result = CloneLargeIconResult(result);
+  cache_.Put(url, entry);
+}
+
+scoped_ptr<favicon_base::LargeIconResult> LargeIconCache::GetCachedResult(
+    const GURL& url) {
+  auto iter = cache_.Get(url);
+  if (iter != cache_.end()) {
+    DCHECK(iter->second->result);
+    return CloneLargeIconResult(*iter->second->result.get());
+  }
+
+  return scoped_ptr<favicon_base::LargeIconResult>();
+}
+
+scoped_ptr<favicon_base::LargeIconResult> LargeIconCache::CloneLargeIconResult(
+    const favicon_base::LargeIconResult& large_icon_result) {
+  scoped_ptr<favicon_base::LargeIconResult> clone;
+  if (large_icon_result.bitmap.is_valid()) {
+    clone.reset(new favicon_base::LargeIconResult(large_icon_result.bitmap));
+  } else {
+    clone.reset(
+        new favicon_base::LargeIconResult(new favicon_base::FallbackIconStyle(
+            *large_icon_result.fallback_icon_style.get())));
+  }
+  return clone.Pass();
+}