Fix race condition in parallel font initialization.

Uses a mutex to guard construction of the singleton, which initialies
the non-threadsafe libfontconfig.  Without this change, the parallel
path ops test runner crashes 6/10 and hangs 2/10 on startup; with this
change, 0/10 problems.

BUG=skia:2693
R=mtklein@google.com, bungeman@google.com, reed@google.com, tomhudson@google.com

Author: tomhudson@chromium.org

Review URL: https://codereview.chromium.org/355573006

1 files changed, 7 insertions, 3 deletions

diff --git a/src/ports/SkFontConfigInterface_direct.cpp b/src/ports/SkFontConfigInterface_direct.cpp
index dc9afbae1f..c0cfd8fdcf 100644
--- a/src/ports/SkFontConfigInterface_direct.cpp
+++ b/src/ports/SkFontConfigInterface_direct.cpp
@@ -124,9 +124,13 @@ private:
     SkMutex mutex_;
 };
 
-SkFontConfigInterface* SkFontConfigInterface::GetSingletonDirectInterface() {
-    SK_DECLARE_STATIC_LAZY_PTR(SkFontConfigInterfaceDirect, direct);
-    return direct.get();
+SkFontConfigInterface* SkFontConfigInterface::GetSingletonDirectInterface(SkBaseMutex* mutex) {
+    SkAutoMutexAcquire ac(mutex);
+    static SkFontConfigInterfaceDirect* singleton = NULL;
+    if (singleton == NULL) {
+        singleton = SkNEW(SkFontConfigInterfaceDirect);
+    }
+    return singleton;
 }
 
 ///////////////////////////////////////////////////////////////////////////////