change SkDrawFilter::filter to return a bool, where false means don't-draw
Review URL: https://codereview.appspot.com/6851111

git-svn-id: http://skia.googlecode.com/svn/trunk@6551 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/gmmain.cpp b/gm/gmmain.cpp
index d4d2154..ebafb8d 100644
--- a/gm/gmmain.cpp
+++ b/gm/gmmain.cpp
@@ -155,12 +155,13 @@
 
 class BWTextDrawFilter : public SkDrawFilter {
 public:
-    virtual void filter(SkPaint*, Type) SK_OVERRIDE;
+    virtual bool filter(SkPaint*, Type) SK_OVERRIDE;
 };
-void BWTextDrawFilter::filter(SkPaint* p, Type t) {
+bool BWTextDrawFilter::filter(SkPaint* p, Type t) {
     if (kText_Type == t) {
         p->setAntiAlias(false);
     }
+    return true;
 }
 
 struct PipeFlagComboData {