make the filter mode for GrTextureAccess an enum so we can plumb down

src/gpu/effects/GrTextureDomainEffect.h

Index: src/gpu/effects/GrTextureDomainEffect.h
diff --git a/src/gpu/effects/GrTextureDomainEffect.h b/src/gpu/effects/GrTextureDomainEffect.h
index a4017c18815f62ba166d56fb1b3cc53d01f96eb0..d07f2fc00692e8b79a5f87f309d55bb2268f8727 100644
--- a/src/gpu/effects/GrTextureDomainEffect.h
+++ b/src/gpu/effects/GrTextureDomainEffect.h
@@ -38,7 +38,7 @@ public:
                                const SkMatrix&,
                                const SkRect& domain,
                                WrapMode,
-                               bool bilerp,
+                               GrTextureParams::FilterMode filterMode,
                                CoordsType = kLocal_CoordsType);
 
     virtual ~GrTextureDomainEffect();
@@ -76,7 +76,7 @@ private:
                           const SkMatrix&,
                           const SkRect& domain,
                           WrapMode,
-                          bool bilerp,
+                          GrTextureParams::FilterMode filterMode,
                           CoordsType type);
 
     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;