Customize SkFontMgr::Factory to control DirectWrite vs. GDI selection

skia/ext/fontmgr_default_win.cc

Index: skia/ext/fontmgr_default_win.cc
diff --git a/skia/ext/fontmgr_default_win.cc b/skia/ext/fontmgr_default_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3d251d0902ece1a7ae565246f3f2fa7d882905a5
--- /dev/null
+++ b/skia/ext/fontmgr_default_win.cc
@@ -0,0 +1,27 @@
+// 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.
+
+#include "skia/ext/fontmgr_default_win.h"
+
+#include "third_party/skia/include/ports/SkFontMgr.h"
+#include "third_party/skia/include/ports/SkTypeface_win.h"
+
+namespace {
+
+SkFontMgr* g_default_fontmgr;
+
+}  // namespace
+
+void SetDefaultSkiaFactory(SkFontMgr* fontmgr) {
+  g_default_fontmgr = fontmgr;
+}
+
+SK_API SkFontMgr* SkFontMgr::Factory() {
+  // This will be set when DirectWrite is in use, and an SkFontMgr has been
+  // created with the pre-sandbox warmed up one. Otherwise, we fallback to a
+  // GDI SkFontMgr which is used in the browser.
+  if (g_default_fontmgr)
+    return g_default_fontmgr;

[bungeman-skia, 2014/06/18 19:49:36]

Note that SkFontMgr is SkRefCnt, so it might make sense to ref this. It may not
make any difference at the moment, but I think that's more correct. The idea was
that this will always create an SkFontMgr, so usually this is creating and then
returning the creation ref. In this case it looks like the global should hold a
ref, and then return a ref each time this is called.

See also skia/ext/refptr.h for Chromium's wrapper around Skia reference
counting, if you're not already familiar with that.

[scottmg, 2014/06/18 20:02:49]

Done.

Just to confirm, the interpretation now is that the raw pointers in content and
now here in g_default_fontmgr are aliases for the initial creation ref, and any
further requests will be additional refs. So, it will never be freed, but that's
sort of what we want in this case. Is that correct?

+  return SkFontMgr_New_GDI();
+}