Implement direct write fallback proxy

content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_DWRITE_FONT_PROXY_MESSAGE_FILTER_WIN_H_
 #define CONTENT_BROWSER_RENDERER_HOST_DWRITE_FONT_PROXY_MESSAGE_FILTER_WIN_H_
 
 #include <dwrite.h>
+#include <dwrite_2.h>
 #include <wrl.h>
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/browser_message_filter.h"
 #include "content/public/browser/browser_thread.h"
 
+struct DWriteFontStyle;
+struct MapCharactersResult;
+
 namespace content {
 
 // Implements a message filter that handles the dwrite font proxy messages.
 // If DWrite is enabled, calls into the system font collection to obtain
 // results. Otherwise, acts as if the system collection contains no fonts.
 class CONTENT_EXPORT DWriteFontProxyMessageFilter
     : public BrowserMessageFilter {
  public:
   DWriteFontProxyMessageFilter();
 
   // BrowserMessageFilter:
   bool OnMessageReceived(const IPC::Message& message) override;
   void OverrideThreadForMessage(const IPC::Message& message,
                                 content::BrowserThread::ID* thread) override;
 
  protected:
   ~DWriteFontProxyMessageFilter() override;
 
   void OnFindFamily(const base::string16& family_name, UINT32* family_index);
   void OnGetFamilyCount(UINT32* count);
   void OnGetFamilyNames(
       UINT32 family_index,
       std::vector<std::pair<base::string16, base::string16>>* family_names);
   void OnGetFontFiles(UINT32 family_index,
                       std::vector<base::string16>* file_paths);
+  void OnMapCharacters(const base::string16& text,
+                       const DWriteFontStyle& font_style,
+                       const base::string16& locale_name,
+                       uint32_t reading_direction,
+                       const base::string16& base_family_name,
+                       MapCharactersResult* result);
 
   void InitializeDirectWrite();
 
  private:
   bool AddFilesForFont(std::set<base::string16>* path_set, IDWriteFont* font);
   bool AddLocalFile(std::set<base::string16>* path_set,
                     IDWriteLocalFontFileLoader* local_loader,
                     IDWriteFontFile* font_file);
 
  private:
   bool direct_write_initialized_ = false;
   Microsoft::WRL::ComPtr<IDWriteFontCollection> collection_;
+  Microsoft::WRL::ComPtr<IDWriteFactory2> factory2_;
+  Microsoft::WRL::ComPtr<IDWriteFontFallback> font_fallback_;
   base::string16 windows_fonts_path_;
 
   DISALLOW_COPY_AND_ASSIGN(DWriteFontProxyMessageFilter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_DWRITE_FONT_PROXY_MESSAGE_FILTER_WIN_H_