alpha threshold bitmap shader

Committed: http://code.google.com/p/skia/source/detail?r=11122

R=reed@google.com

Author: bsalomon@google.com

Review URL: https://chromiumcodereview.appspot.com/23707019

git-svn-id: http://skia.googlecode.com/svn/trunk@11131 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrTextureAccess.h b/include/gpu/GrTextureAccess.h
index 0f44807..f8bb554 100644
--- a/include/gpu/GrTextureAccess.h
+++ b/include/gpu/GrTextureAccess.h
@@ -18,7 +18,7 @@
  * Represents the filtering and tile modes used to access a texture. It is mostly used with
  * GrTextureAccess (defined below). Also, some of the texture cache methods require knowledge about
  * filtering and tiling to perform a cache lookup. If it wasn't for this latter usage this would
- * be folded into GrTextureAccess.
+ * be folded into GrTextureAccess. The default is clamp tile modes and no filtering.
  */
 class GrTextureParams {
 public: