Allow default texture cache limit to be set within gyp.

Review URL: https://codereview.appspot.com/6818051

git-svn-id: http://skia.googlecode.com/svn/trunk@6177 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrUserConfig.h b/include/gpu/GrUserConfig.h
index d514486..7b4e4bb 100644
--- a/include/gpu/GrUserConfig.h
+++ b/include/gpu/GrUserConfig.h
@@ -54,6 +54,12 @@
  */
 //#define GR_GEOM_BUFFER_LOCK_THRESHOLD (1<<15)
 
+/**
+ * This gives a threshold in megabytes for the maximum size of the texture cache
+ * in vram. The value is only a default and can be overridden at runtime.
+ */
+//#define GR_DEFAULT_TEXTURE_CACHE_MB_LIMIT 96
+
 ///////////////////////////////////////////////////////////////////////////////
 // Decide Ganesh types