[ios] Adds GoogleLogoService to help with fetching doodles.

ios/chrome/browser/google/google_logo_service.mm

+// 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.
+
+#include "ios/chrome/browser/google/google_logo_service.h"
+
+#import <Foundation/Foundation.h>
+
+#include "base/bind.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "components/search_engines/template_url_service.h"
+#include "components/search_provider_logos/google_logo_api.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/search_engines/template_url_service_factory.h"
+#include "ios/chrome/browser/search_engines/ui_thread_search_terms_data.h"
+#include "ios/web/public/web_thread.h"
+#include "net/url_request/url_request_context_getter.h"
+#include "ui/gfx/image/image.h"
+
+using search_provider_logos::Logo;
+using search_provider_logos::LogoDelegate;
+using search_provider_logos::LogoTracker;
+
+namespace {
+
+const char kGoogleDoodleURLPath[] = "async/newtab_mobile";
+static NSArray* const kDoodleCacheDirectory = @[ @"Chromium", @"Doodle" ];
+
+// Cache directory for doodle.
+base::FilePath DoodleDirectory() {
+  NSArray* paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory,
+                                                       NSUserDomainMask, YES);
+  NSString* path = [paths objectAtIndex:0];
+  NSArray* path_components =
+      [NSArray arrayWithObjects:path, kDoodleCacheDirectory[0],
+                                kDoodleCacheDirectory[1], nil];
+  return base::FilePath(
+      base::SysNSStringToUTF8([NSString pathWithComponents:path_components]));
+}
+
+// Returns the URL where the doodle can be downloaded, e.g.
+// https://www.google.com/async/newtab_mobile. This depends on the user's
+// Google domain.
+GURL GetGoogleDoodleURL(ios::ChromeBrowserState* browser_state) {
+  GURL google_base_url(
+      ios::UIThreadSearchTermsData(browser_state).GoogleBaseURLValue());
+  // SetPathStr() requires its argument to stay in scope as long as
+  // |replacements| is, so a std::string is needed, instead of a char*.
+  std::string path = kGoogleDoodleURLPath;
+  GURL::Replacements replacements;
+  replacements.SetPathStr(path);
+
+  return google_base_url.ReplaceComponents(replacements);
+}
+
+class IOSChromeLogoDelegate : public search_provider_logos::LogoDelegate {
+ public:
+  IOSChromeLogoDelegate() {}
+  ~IOSChromeLogoDelegate() override {}
+
+  // search_provider_logos::LogoDelegate implementation.
+  void DecodeUntrustedImage(
+      const scoped_refptr<base::RefCountedString>& encoded_image,
+      base::Callback<void(const SkBitmap&)> image_decoded_callback) override {
+    SkBitmap bitmap = gfx::Image::CreateFrom1xPNGBytes(encoded_image->front(),
+                                                       encoded_image->size())
+                          .AsBitmap();
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(image_decoded_callback, bitmap));
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(IOSChromeLogoDelegate);
+};
+
+}  // namespace
+
+GoogleLogoService::GoogleLogoService(ios::ChromeBrowserState* browser_state)
+    : browser_state_(browser_state) {}
+
+GoogleLogoService::~GoogleLogoService() {}
+
+void GoogleLogoService::GetLogo(search_provider_logos::LogoObserver* observer) {
+  TemplateURLService* template_url_service =
+      ios::TemplateURLServiceFactory::GetForBrowserState(browser_state_);
+  if (!template_url_service)
+    return;
+
+  TemplateURL* template_url = template_url_service->GetDefaultSearchProvider();
+  if (!template_url ||
+      !template_url->url_ref().HasGoogleBaseURLs(
+          template_url_service->search_terms_data()))
+    return;
+
+  if (!logo_tracker_) {
+    logo_tracker_.reset(new LogoTracker(
+        DoodleDirectory(),
+        web::WebThread::GetTaskRunnerForThread(web::WebThread::FILE),
+        web::WebThread::GetBlockingPool(), browser_state_->GetRequestContext(),
+        std::unique_ptr<search_provider_logos::LogoDelegate>(
+            new IOSChromeLogoDelegate())));
+  }
+
+  logo_tracker_->SetServerAPI(
+      GetGoogleDoodleURL(browser_state_),
+      base::Bind(&search_provider_logos::GoogleParseLogoResponse),
+      base::Bind(&search_provider_logos::GoogleAppendQueryparamsToLogoURL),
+      true, false /* transparent */);
+  logo_tracker_->GetLogo(observer);
+}
+
+void GoogleLogoService::SetCachedLogo(const search_provider_logos::Logo* logo) {
+  if (logo) {
+    if (cached_metadata_.fingerprint == logo->metadata.fingerprint) {
+      return;
+    }
+    logo->image.deepCopyTo(&cached_image_);
+    cached_metadata_ = logo->metadata;
+  } else {
+    cached_image_ = SkBitmap();
+    cached_metadata_ = empty_metadata;
+  }
+}
+
+search_provider_logos::Logo GoogleLogoService::GetCachedLogo() {
+  search_provider_logos::Logo logo;
+  logo.image = cached_image_;
+  logo.metadata = cached_metadata_;
+  return logo;
+}