Remove some unused history resources on iOS

ios/chrome/browser/ui/webui/history/favicon_source.h

-// 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.
-
-#ifndef IOS_CHROME_BROWSER_UI_WEBUI_HISTORY_FAVICON_SOURCE_H_
-#define IOS_CHROME_BROWSER_UI_WEBUI_HISTORY_FAVICON_SOURCE_H_
-
-#include <map>
-#include <string>
-
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/task/cancelable_task_tracker.h"
-#include "components/favicon/core/favicon_service.h"
-#include "ios/web/public/url_data_source_ios.h"
-#include "ui/gfx/favicon_size.h"
-
-namespace favicon {
-class FaviconService;
-}
-
-namespace history {
-class TopSites;
-}
-
-namespace syncer {
-class SyncService;
-}
-
-// FaviconSource is the gateway between network-level chrome:
-// requests for favicons and the history backend that serves these.
-//
-// Format:
-//   chrome://favicon/size&scalefactor/urlmodifier/url
-// Some parameters are optional as described below. However, the order of the
-// parameters is not interchangeable.
-//
-// Parameter:
-//  'url'               Required
-//    Specifies the page URL of the requested favicon. If the 'urlmodifier'
-//    parameter is 'iconurl', the URL refers to the URL of the favicon image
-//    instead.
-//  'size&scalefactor'  Optional
-//    Values: ['largest', size/aa@bx/]
-//    'largest': Specifies that the largest available favicon is requested.
-//      Example: chrome://favicon/largest/http://www.google.com/
-//    'size/aa@bx/':
-//      Specifies the requested favicon's size in DIP (aa) and the requested
-//      favicon's scale factor. (b).
-//      The supported requested DIP sizes are: 16x16, 32x32 and 64x64.
-//      If the parameter is unspecified, the requested favicon's size defaults
-//      to 16 and the requested scale factor defaults to 1x.
-//      Example: chrome://favicon/size/16@2x/http://www.google.com/
-//  'urlmodifier'       Optional
-//    Values: ['iconurl', 'origin']
-//    'iconurl': Specifies that the url parameter refers to the URL of
-//    the favicon image as opposed to the URL of the page that the favicon is
-//    on.
-//    Example: chrome://favicon/iconurl/http://www.google.com/favicon.ico
-//    'origin': Specifies that the URL should be converted to a form with
-//    an empty path and a valid scheme. The converted URL will be used to
-//    request the favicon from the favicon service.
-//    Examples:
-//      chrome://favicon/origin/http://example.com/a
-//      chrome://favicon/origin/example.com
-//        Both URLs request the favicon for http://example.com from the
-//        favicon service.
-class FaviconSource : public web::URLDataSourceIOS {
- public:
-  // |favicon_service|, |top_sites| and |sync_service| can be null.
-  FaviconSource(favicon::FaviconService* favicon_service,
-                const scoped_refptr<history::TopSites>& top_sites,
-                syncer::SyncService* sync_service);
-
-  ~FaviconSource() override;
-
-  // web::URLDataSourceIOS implementation.
-  std::string GetSource() const override;
-  void StartDataRequest(
-      const std::string& path,
-      const web::URLDataSourceIOS::GotDataCallback& callback) override;
-  std::string GetMimeType(const std::string&) const override;
-  bool ShouldReplaceExistingSource() const override;
-
- protected:
-  struct IconRequest {
-    IconRequest();
-    IconRequest(const web::URLDataSourceIOS::GotDataCallback& cb,
-                const GURL& path,
-                int size,
-                float scale);
-    IconRequest(const IconRequest& other);
-    ~IconRequest();
-
-    web::URLDataSourceIOS::GotDataCallback callback;
-    GURL request_path;
-    int size_in_dip;
-    float device_scale_factor;
-  };
-
-  // Called when the favicon data is missing to perform additional checks to
-  // locate the resource.
-  // |request| contains information for the failed request.
-  // Returns true if the missing resource is found.
-  virtual bool HandleMissingResource(const IconRequest& request);
-
- private:
-  // Defines the allowed pixel sizes for requested favicons.
-  enum IconSize { SIZE_16, SIZE_32, SIZE_64, NUM_SIZES };
-
-  // Called when favicon data is available from the history backend.
-  void OnFaviconDataAvailable(
-      const IconRequest& request,
-      const favicon_base::FaviconRawBitmapResult& bitmap_result);
-
-  // Sends the 16x16 DIP 1x default favicon.
-  void SendDefaultResponse(
-      const web::URLDataSourceIOS::GotDataCallback& callback);
-
-  // Sends the default favicon.
-  void SendDefaultResponse(const IconRequest& request);
-
-  favicon::FaviconService* favicon_service_;
-  scoped_refptr<history::TopSites> top_sites_;
-  syncer::SyncService* sync_service_;
-
-  base::CancelableTaskTracker cancelable_task_tracker_;
-
-  // Raw PNG representations of favicons of each size to show when the favicon
-  // database doesn't have a favicon for a webpage. Indexed by IconSize values.
-  scoped_refptr<base::RefCountedMemory> default_favicons_[NUM_SIZES];
-
-  DISALLOW_COPY_AND_ASSIGN(FaviconSource);
-};
-
-#endif  // IOS_CHROME_BROWSER_UI_WEBUI_HISTORY_FAVICON_SOURCE_H_