Fix thread unsafe mutex initialization.

BUG=skia:2779
R=robertphillips@google.com, mtklein@google.com, reed@android.com, bsalomon@google.com

Author: bungeman@google.com

Review URL: https://codereview.chromium.org/419113002
diff --git a/src/gpu/GrDrawTargetCaps.h b/src/gpu/GrDrawTargetCaps.h
index dcea79e..b979b53 100644
--- a/src/gpu/GrDrawTargetCaps.h
+++ b/src/gpu/GrDrawTargetCaps.h
@@ -17,7 +17,7 @@
  */
 class GrDrawTargetCaps : public SkRefCnt {
 public:
-    SK_DECLARE_INST_COUNT(Caps)
+    SK_DECLARE_INST_COUNT(GrDrawTargetCaps)
 
     GrDrawTargetCaps() { this->reset(); }
     GrDrawTargetCaps(const GrDrawTargetCaps& other) : INHERITED() { *this = other; }