Don't declare displayCache variable if PROGRAM_CACHE_STATS not defined.

BUG=
R=robertphillips@google.com

Review URL: https://codereview.chromium.org/23757053

git-svn-id: http://skia.googlecode.com/svn/trunk/src@11301 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/gl/GrGpuGL_program.cpp b/gpu/gl/GrGpuGL_program.cpp
index 7576af6..8a3444e 100644
--- a/gpu/gl/GrGpuGL_program.cpp
+++ b/gpu/gl/GrGpuGL_program.cpp
@@ -12,8 +12,10 @@
 #include "SkRTConf.h"
 #include "SkTSearch.h"
 
+#ifdef PROGRAM_CACHE_STATS
 SK_CONF_DECLARE(bool, c_DisplayCache, "gpu.displayCache", false,
                 "Display program cache usage.");
+#endif
 
 typedef GrGLUniformManager::UniformHandle UniformHandle;