Turn on quilt mode in DM.

gm/shallowgradient.cpp

Index: gm/shallowgradient.cpp
diff --git a/gm/shallowgradient.cpp b/gm/shallowgradient.cpp
index fd149433956002452795c6f6e97195a0a9132b3d..a2b29d37ed8064632d7a38affa7f8a1a8d6d9538 100644
--- a/gm/shallowgradient.cpp
+++ b/gm/shallowgradient.cpp
@@ -42,6 +42,13 @@ public:
     }
 
 protected:
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        if (fName.contains("linear") || fName.contains("radial")) {
+            return kSkipTiled_Flag;
+        }
+        return 0;
+    }
+
     virtual SkString onShortName() SK_OVERRIDE {
         return fName;
     }