Split atomic and mutex implementations and make inlinable.

include/core/SkWeakRefCnt.h

Index: include/core/SkWeakRefCnt.h
===================================================================
--- include/core/SkWeakRefCnt.h	(revision 12696)
+++ include/core/SkWeakRefCnt.h	(working copy)
@@ -89,9 +89,9 @@
     */
     bool SK_WARN_UNUSED_RESULT try_ref() const {
         if (sk_atomic_conditional_inc(&fRefCnt) != 0) {
-            // Aquire barrier (L/SL), if not provided above.
+            // Acquire barrier (L/SL), if not provided above.
             // Prevents subsequent code from happening before the increment.
-            sk_membar_aquire__after_atomic_conditional_inc();
+            sk_membar_acquire__after_atomic_conditional_inc();
             return true;
         }
         return false;
@@ -115,9 +115,9 @@
         SkASSERT(fWeakCnt > 0);
         // Release barrier (SL/S), if not provided below.
         if (sk_atomic_dec(&fWeakCnt) == 1) {
-            // Aquire barrier (L/SL), if not provided above.
+            // Acquire barrier (L/SL), if not provided above.
             // Prevents code in destructor from happening before the decrement.
-            sk_membar_aquire__after_atomic_dec();
+            sk_membar_acquire__after_atomic_dec();
 #ifdef SK_DEBUG
             // so our destructor won't complain
             fWeakCnt = 1;