Add logic to switch to DirectWrite font proxy via field trial.

content/public/common/dwrite_font_platform_win.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 CONTENT_PUBLIC_COMMON_DWRITE_FONT_PLATFORM_WIN_H_
 #define CONTENT_PUBLIC_COMMON_DWRITE_FONT_PLATFORM_WIN_H_
 
 #include "base/files/file.h"
 #include "content/common/content_export.h"
 
@@ skipping 18 matching lines @@
 CONTENT_EXPORT bool BuildFontCache(const base::FilePath& file);
 
 // Loads font cache from file. This is supposed to be used from browser
 // side where loading means creating readonly shared memory file mapping so that
 // renderers can read from it.
 CONTENT_EXPORT bool LoadFontCache(const base::FilePath& path);
 
 // Added in header mainly for unittest
 CONTENT_EXPORT bool ValidateFontCacheFile(base::File* file);
 
+// Determines whether code should use the DirectWrite font proxy codepathh.

[fdoray, 2015/12/30 01:15:08]

*codepath

[Ilya Kulshin, 2015/12/30 01:59:46]

Done.

+// Note that this function only checks whether the field trial is enabled.
+// Callers are still expected to take appropriate action based on the return
+// value.
+CONTENT_EXPORT bool ShouldUseDirectWriteFontProxyFieldTrial();
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_DWRITE_FONT_PLATFORM_WIN_H_