Replace uses of GR_DEBUG by SK_DEBUG.

BUG=None
R=bsalomon@google.com, robertphillips@google.com

Author: tfarina@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23137022

git-svn-id: http://skia.googlecode.com/svn/trunk@10978 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/gr_unittests.cpp b/src/gpu/gr_unittests.cpp
index a6a43c4..f586a94 100644
--- a/src/gpu/gr_unittests.cpp
+++ b/src/gpu/gr_unittests.cpp
@@ -17,7 +17,7 @@
 // If we aren't inheriting these as #defines from elsewhere,
 // clang demands they be declared before we #include the template
 // that relies on them.
-#if GR_DEBUG
+#ifdef SK_DEBUG
 static bool LT(const int& elem, int value) {
     return elem < value;
 }