In Debug, SkMutex(pthread) crashes on re-entrant aquire from same thread.

src/ports/SkMutex_pthread.h

Index: src/ports/SkMutex_pthread.h
diff --git a/src/ports/SkMutex_pthread.h b/src/ports/SkMutex_pthread.h
index 1904140c4cc651f2c7b5bf3191a7c97e81f8591d..662e549f12e65dd29cc6cd2b632327e8a026afea 100644
--- a/src/ports/SkMutex_pthread.h
+++ b/src/ports/SkMutex_pthread.h
@@ -19,6 +19,7 @@
 // a corresponding static finalizer).
 struct SkBaseMutex {
     void acquire() {
+        SkASSERT(fOwner != pthread_self());  // SkMutex is not re-entrant

[mtklein, 2014/06/20 15:34:31]

Run this through the TSAN bot before submitting?  It may complain that this
isn't thread safe.  If so, wrap fOwner is SK_ANNOTATE_UNPROTECTED_READ.

         pthread_mutex_lock(&fMutex);
         SkDEBUGCODE(fOwner = pthread_self();)
     }