GrRedBlackTree test is GPU specific.

tests/GrRedBlackTreeTest.cpp

Index: tests/GrRedBlackTreeTest.cpp
diff --git a/tests/GrRedBlackTreeTest.cpp b/tests/GrRedBlackTreeTest.cpp
index c3aa14b1a332f0a3b25324f17bcdee7290475768..bb0fa156fa236a31100330e4458216dd4b6441f2 100644
--- a/tests/GrRedBlackTreeTest.cpp
+++ b/tests/GrRedBlackTreeTest.cpp
@@ -5,6 +5,9 @@
  * found in the LICENSE file.
  */
 
+// This is a GPU-backend specific test
+#if SK_SUPPORT_GPU
+
 #include "GrRedBlackTree.h"
 #include "SkRandom.h"
 #include "Test.h"
@@ -178,3 +181,5 @@ DEF_TEST(GrRedBlackTreeTest, reporter) {
     // test reset on empty tree.
     tree.reset();
 }
+
+#endif