Create direct write font proxy classes and unit tests.

content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h

Index: content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h
diff --git a/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h b/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..428ee27e895fe634a1cf2728c2f27b395044ad66
--- /dev/null
+++ b/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.h
@@ -0,0 +1,64 @@
+// 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 <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"
+
+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();
+  ~DWriteFontProxyMessageFilter() override;
+
+  // BrowserMessageFilter:
+  bool OnMessageReceived(const IPC::Message& message) override;
+  void OverrideThreadForMessage(const IPC::Message& message,
+                                content::BrowserThread::ID* thread) override;
+
+ protected:
+  void OnFindFamily(const base::string16& family_name, uint32* family_index);

[Alexei Svitkine (slow), 2015/11/25 20:17:45]

Please eliminate all uses of uint32 in the code. Either switch to uint32_t, if
it doesn't have any dependencies on  external API types, or use the external API
types (i.e. UINT32 capitalized).

[Ilya Kulshin, 2015/12/02 02:23:01]

Done.

+  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 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_;
+  base::string16 windows_fonts_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(DWriteFontProxyMessageFilter);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_DWRITE_FONT_PROXY_MESSAGE_FILTER_WIN_H_