Remove mutex for retrieving default typeface.

src/core/SkTypeface.cpp

 /*
  * Copyright 2011 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAdvancedTypefaceMetrics.h"
 #include "SkEndian.h"
 #include "SkFontDescriptor.h"
@@ skipping 60 matching lines @@
         return new EmptyLocalizedStrings;
     };
     int onGetTableTags(SkFontTableTag tags[]) const override { return 0; }
     size_t onGetTableData(SkFontTableTag, size_t, size_t, void*) const override {
         return 0;
     }
 };
 
 }
 
-SK_DECLARE_STATIC_MUTEX(gCreateDefaultMutex);
-
 SkTypeface* SkTypeface::GetDefaultTypeface(Style style) {
     static SkOnce once[4];
     static SkTypeface* defaults[4];
 
     SkASSERT((int)style < 4);
     once[style]([style] {
-        // It is not safe to call FontConfigTypeface::LegacyCreateTypeface concurrently.
-        // To be safe, we serialize here with a mutex so only one call to
-        // CreateTypeface is happening at any given time.
-        // TODO(bungeman, mtklein): This is sad.  Make our fontconfig code safe?
-        SkAutoMutexAcquire lock(&gCreateDefaultMutex);
         SkAutoTUnref<SkFontMgr> fm(SkFontMgr::RefDefault());
         SkTypeface* t = fm->legacyCreateTypeface(nullptr, SkFontStyle::FromOldStyle(style));
         defaults[style] = t ? t : SkEmptyTypeface::Create();
     });
     return defaults[style];
 }
 
 sk_sp<SkTypeface> SkTypeface::MakeDefault(Style style) {
     return sk_ref_sp(GetDefaultTypeface(style));
 }
@@ skipping 246 matching lines @@
     SkAutoTDelete<SkScalerContext> ctx(this->createScalerContext(noeffects, desc, true));
     if (ctx.get()) {
         SkPaint::FontMetrics fm;
         ctx->getFontMetrics(&fm);
         bounds->set(fm.fXMin * invTextSize, fm.fTop * invTextSize,
                     fm.fXMax * invTextSize, fm.fBottom * invTextSize);
         return true;
     }
     return false;
 }