Adding more validation

gm/imagefiltersbase.cpp

Index: gm/imagefiltersbase.cpp
diff --git a/gm/imagefiltersbase.cpp b/gm/imagefiltersbase.cpp
index 2c8fceb1461ed9dcae892dfe9da9523412c87a94..d237de39509a11f335fc7a2d4a4113c4f2cd3940 100644
--- a/gm/imagefiltersbase.cpp
+++ b/gm/imagefiltersbase.cpp
@@ -27,7 +27,8 @@ protected:
         return false;
     }
 
-    FailImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
+    FailImageFilter(SkFlattenableReadBuffer& buffer)
+      : INHERITED(buffer, SkImageFilter::kOneInput) {}
 
 private:
     typedef SkImageFilter INHERITED;
@@ -50,7 +51,8 @@ protected:
         return true;
     }
 
-    IdentityImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
+    IdentityImageFilter(SkFlattenableReadBuffer& buffer)
+      : INHERITED(buffer, SkImageFilter::kOneInput) {}
 
 private:
     typedef SkImageFilter INHERITED;