Add plumbing in blink to allow overriding the default font collection.

third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Computer, Inc.
  * Copyright (c) 2006, 2007, 2008, 2009, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 79 matching lines @@
 // static
 void FontCache::setStatusFontMetrics(const wchar_t* familyName, int32_t fontHeight)
 {
     s_statusFontFamilyName = new AtomicString(familyName);
     s_statusFontHeight = ensureMinimumFontHeightIfNeeded(fontHeight);
 }
 
 FontCache::FontCache()
     : m_purgePreventCount(0)
 {
-    SkFontMgr* fontManager;
-
-    if (s_useDirectWrite) {
-        fontManager = SkFontMgr_New_DirectWrite(s_directWriteFactory);
-        s_useSubpixelPositioning = true;
+    if (s_fontManager) {
+        adopted(s_fontManager);

[bungeman-chromium, 2016/02/09 22:25:17]

The adoption checks are only done in debug, so 'adopted' only exists in debug.

[jbroman, 2016/02/09 22:31:30]

Well, it does exist here:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...
as long as PassRefPtr.h is included, and this is called as WTF::adopted (I don't
think ADL will work here?), this should work?

[bungeman-chromium, 2016/02/09 22:36:05]

Note that adding 'using WTF::adopted' should work to fix release. I haven't
verified that though (or if that is a good idea). This is being provided in
debug from sk_ref_cnt_ext_debug.h (and isn't from sk_ref_cnt_ext_release.h). I
would rely on someone more familiar with Blink's reference counting for real
advice though.

This seems to be complicated by the 'rel' trybots actually being 'debug with
optimizations' as opposed to the 'rel' bots on the waterfall which are actually
'release'.

+        m_fontManager = s_fontManager;
+    } else if (s_useDirectWrite) {
+        m_fontManager = adoptRef(SkFontMgr_New_DirectWrite());

[bungeman-chromium, 2016/02/04 21:40:32]

I'm assuming this is only true then not running in the sandbox.

[Ilya Kulshin, 2016/02/05 02:02:47]

Yes, I believe this case only happens during tests when not using the sandbox.
This codepath would not work if run during the sandbox (we would be unable to
get any fonts).

     } else {
-        fontManager = SkFontMgr_New_GDI();
-        // Subpixel text positioning is not supported by the GDI backend.
-        s_useSubpixelPositioning = false;
+        m_fontManager = adoptRef(SkFontMgr_New_GDI());
     }
 
-    ASSERT(fontManager);
-    m_fontManager = adoptPtr(fontManager);
+    // Subpixel text positioning is only supported by the DirectWrite backend (not GDI).
+    s_useSubpixelPositioning = s_useDirectWrite;
+
+    ASSERT(m_fontManager.get());
 }
 
 
 // Given the desired base font, this will create a SimpleFontData for a specific
 // font that can be used to render the given range of characters.
 PassRefPtr<SimpleFontData> FontCache::fallbackFontForCharacter(
     const FontDescription& fontDescription, UChar32 character,
     const SimpleFontData* originalFontData)
 {
     // First try the specified font with standard style & weight.
@@ skipping 297 matching lines @@
         if (typefacesMatchesFamily(tf.get(), family)) {
             result->setMinSizeForSubpixel(minSizeForSubpixelForFont);
             break;
         }
     }
 
     return result.release();
 }
 
 } // namespace blink