Creates FaviconAttributesProvider.

ios/chrome/browser/favicon/favicon_attributes_provider.mm

+// Copyright 2016 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/favicon/favicon_attributes_provider.h"
+
+#include "base/logging.h"
+#include "base/mac/bind_objc_block.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/task/cancelable_task_tracker.h"
+#include "components/favicon/core/fallback_url_util.h"
+#include "components/favicon/core/large_icon_service.h"
+#include "components/favicon_base/fallback_icon_style.h"
+#include "components/favicon_base/favicon_types.h"
+#include "skia/ext/skia_utils_ios.h"
+#include "url/gurl.h"
+
+@interface FaviconAttributesProvider () {
+  // Used to cancel tasks for the LargeIconService.
+  base::CancelableTaskTracker _faviconTaskTracker;
+}
+
+@end
+
+@implementation FaviconAttributesProvider
+@synthesize largeIconService = _largeIconService;
+@synthesize minSize = _minSize;
+@synthesize faviconSize = _faviconSize;
+
+- (instancetype _Nonnull)
+initWithFaviconSize:(CGFloat)faviconSize
+     minFaviconSize:(CGFloat)minFaviconSize
+   largeIconService:(favicon::LargeIconService* _Nonnull)largeIconService {
+  DCHECK(largeIconService);

[jif, 2016/09/26 10:58:13]

is the DCHECK necessary if largeIconService is _Nonnull ?

[stkhapugin, 2016/09/26 15:51:36]

Yes, because nullability markers are not tightly enforced, it's pretty easy to
accidentally pass a nil value here. For example, calling this with
"largeIconService:nil" will issue a warning, but calling this with
"largeIconService:[LargeIconServiceFactory iconService]" would only issue a
warning if LargeIconServiceFactory.h uses nullability markers afaik. 

+  self = [super init];
+  if (self) {
+    _faviconSize = faviconSize;
+    _minSize = minFaviconSize;
+    _largeIconService = largeIconService;
+  }
+
+  return self;
+}
+
+- (void)fetchFaviconAttributesForURL:(const GURL&)URL
+                          completion:
+                              (void (^_Nonnull)(FaviconAttributes* _Nonnull))
+                                  completion {
+  GURL blockURL(URL);
+  void (^faviconBlock)(const favicon_base::LargeIconResult&) =
+      ^(const favicon_base::LargeIconResult& result) {
+        FaviconAttributes* attributes = nil;
+        if (result.bitmap.is_valid()) {
+          scoped_refptr<base::RefCountedMemory> data =
+              result.bitmap.bitmap_data.get();
+          UIImage* favicon =
+              [UIImage imageWithData:[NSData dataWithBytes:data->front()
+                                                    length:data->size()]];
+          attributes = [FaviconAttributes attributesWithImage:favicon];
+        } else if (result.fallback_icon_style) {
+          UIColor* backgroundColor = skia::UIColorFromSkColor(
+              result.fallback_icon_style->background_color);
+          UIColor* textColor =
+              skia::UIColorFromSkColor(result.fallback_icon_style->text_color);
+          NSString* monogram =
+              base::SysUTF16ToNSString(favicon::GetFallbackIconText(blockURL));
+          attributes =
+              [FaviconAttributes attributesWithMonogram:monogram
+                                              textColor:textColor
+                                        backgroundColor:backgroundColor];
+        }
+        DCHECK(attributes);
+        completion(attributes);
+      };
+
+  // Always call LargeIconService in case the favicon was updated.
+  CGFloat faviconSize = [UIScreen mainScreen].scale * self.faviconSize;
+  CGFloat minFaviconSize = [UIScreen mainScreen].scale * self.minSize;
+  self.largeIconService->GetLargeIconOrFallbackStyle(
+      URL, minFaviconSize, faviconSize, base::BindBlock(faviconBlock),
+      &_faviconTaskTracker);
+}
+@end