Initialize font fallback when creating DWrite font manager

include/ports/SkTypeface_win.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTypeface_win_DEFINED
 #define SkTypeface_win_DEFINED
 
@@ skipping 23 matching lines @@
   *  remotely (re)loaded.
   */
 SK_API void SkTypeface_SetEnsureLOGFONTAccessibleProc(void (*)(const LOGFONT&));
 
 // Experimental!
 //
 class SkFontMgr;
 class SkRemotableFontMgr;
 struct IDWriteFactory;
 struct IDWriteFontCollection;
+struct IDWriteFontFallback;
 
 SK_API SkFontMgr* SkFontMgr_New_GDI();
 SK_API SkFontMgr* SkFontMgr_New_DirectWrite(IDWriteFactory* factory = NULL,

[reed1, 2016/03/01 14:05:42]

Nit: this function is getting too many default args. Lets create a version that
takes all its parameters explicitly.

[Ilya Kulshin, 2016/03/07 23:42:04]

Reworked this patch so that the extra arg is no longer needed (that wasn't the
reason for reworking the patch).

-                                            IDWriteFontCollection* collection = NULL);
+                                            IDWriteFontCollection* collection = NULL,
+                                            IDWriteFontFallback* fallback = NULL);
 
 /**
  *  Creates an SkFontMgr which renders using DirectWrite and obtains its data
  *  from the SkRemotableFontMgr.
  *
  *  If DirectWrite could not be initialized, will return NULL.
  */
 SK_API SkFontMgr* SkFontMgr_New_DirectWriteRenderer(SkRemotableFontMgr*);
 
 /**
  *  Creates an SkRemotableFontMgr backed by DirectWrite using the default
  *  system font collection in the current locale.
  *
  *  If DirectWrite could not be initialized, will return NULL.
  */
 SK_API SkRemotableFontMgr* SkRemotableFontMgr_New_DirectWrite();
 
 #endif  // SK_BUILD_FOR_WIN
 #endif  // SkTypeface_win_DEFINED