Revert of SK_DECLARE_STATIC_MUTEX -> static SkMutex

dm/DMJsonWriter.cpp

Index: dm/DMJsonWriter.cpp
diff --git a/dm/DMJsonWriter.cpp b/dm/DMJsonWriter.cpp
index 652c70b8cc72e9c2364da6e6337f059a230edef8..7bd8acd6d2d989e070c0d3a380ced8303f29c2af 100644
--- a/dm/DMJsonWriter.cpp
+++ b/dm/DMJsonWriter.cpp
@@ -19,7 +19,7 @@
 namespace DM {
 
 SkTArray<JsonWriter::BitmapResult> gBitmapResults;
-static SkMutex gBitmapResultLock;
+SK_DECLARE_STATIC_MUTEX(gBitmapResultLock);
 
 void JsonWriter::AddBitmapResult(const BitmapResult& result) {
     SkAutoMutexAcquire lock(&gBitmapResultLock);
@@ -27,7 +27,7 @@
 }
 
 SkTArray<skiatest::Failure> gFailures;
-static SkMutex gFailureLock;
+SK_DECLARE_STATIC_MUTEX(gFailureLock);
 
 void JsonWriter::AddTestFailure(const skiatest::Failure& failure) {
     SkAutoMutexAcquire lock(gFailureLock);