Atomics overhaul.

include/core/SkMutex.h

Index: include/core/SkMutex.h
diff --git a/include/core/SkMutex.h b/include/core/SkMutex.h
index 7dbe957d8b12b70758875ec3bb8997051f335684..ea7e81726b88c05828f35753c877b129eab2a15d 100644
--- a/include/core/SkMutex.h
+++ b/include/core/SkMutex.h
@@ -10,4 +10,44 @@
     #include "../ports/SkMutex_pthread.h"
 #endif
 
+class SkAutoMutexAcquire : SkNoncopyable {
+public:
+    explicit SkAutoMutexAcquire(SkBaseMutex& mutex) : fMutex(&mutex) {
+        SkASSERT(fMutex != NULL);
+        mutex.acquire();
+    }
+
+    explicit SkAutoMutexAcquire(SkBaseMutex* mutex) : fMutex(mutex) {
+        if (mutex) {
+            mutex->acquire();
+        }
+    }
+
+    /** If the mutex has not been released, release it now. */
+    ~SkAutoMutexAcquire() {
+        if (fMutex) {
+            fMutex->release();
+        }
+    }
+
+    /** If the mutex has not been released, release it now. */
+    void release() {
+        if (fMutex) {
+            fMutex->release();
+            fMutex = NULL;
+        }
+    }
+
+    /** Assert that we're holding the mutex. */
+    void assertHeld() {
+        SkASSERT(fMutex);
+        fMutex->assertHeld();
+    }
+
+private:
+    SkBaseMutex* fMutex;
+};
+#define SkAutoMutexAcquire(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexAcquire)
+
+
 #endif//SkMutex_DEFINED