[ios] Adds GoogleLogoService to help with fetching doodles.

ios/chrome/browser/google/google_logo_service.h

+// Copyright 2014 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.
+
+#ifndef IOS_CHROME_BROWSER_GOOGLE_GOOGLE_LOGO_SERVICE_H_
+#define IOS_CHROME_BROWSER_GOOGLE_GOOGLE_LOGO_SERVICE_H_
+
+#include <memory>
+
+#include "components/keyed_service/core/keyed_service.h"
+#include "components/search_provider_logos/logo_tracker.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+
+namespace ios {
+class ChromeBrowserState;
+}
+
+// Provides the logo if a BrowserState's default search provider is Google.
+//
+// Example usage:
+//   GoogleLogoService* logo_service =
+//       GoogleLogoServiceFactory::GetForBrowserState(browser_state);
+//   logo_service->GetLogo(...);
+//
+class GoogleLogoService : public KeyedService {
+ public:
+  explicit GoogleLogoService(ios::ChromeBrowserState* browser_state);
+  ~GoogleLogoService() override;
+
+  // Gets the logo for the default search provider and notifies |observer|
+  // with the results.
+  void GetLogo(search_provider_logos::LogoObserver* observer);
+
+  // |LogoTracker| does everything on callbacks, and iOS needs to load the logo
+  // immediately on page load. This caches the SkBitmap so we can immediately
+  // load. This prevents showing the google logo on every new tab page and
+  // immediately animating to the logo. Only one SkBitmap is cached per
+  // BrowserState.
+  void SetCachedLogo(const search_provider_logos::Logo* logo);
+  search_provider_logos::Logo GetCachedLogo();
+
+ private:
+  ios::ChromeBrowserState* browser_state_;
+  std::unique_ptr<search_provider_logos::LogoTracker> logo_tracker_;
+  SkBitmap cached_image_;
+  search_provider_logos::LogoMetadata cached_metadata_;
+  const search_provider_logos::LogoMetadata empty_metadata;
+
+  DISALLOW_COPY_AND_ASSIGN(GoogleLogoService);
+};
+
+#endif  // IOS_CHROME_BROWSER_GOOGLE_GOOGLE_LOGO_SERVICE_H_