Add device space skshader GM to test kDevice_GrCoordSet

include/gpu/GrColor.h

Index: include/gpu/GrColor.h
diff --git a/include/gpu/GrColor.h b/include/gpu/GrColor.h
index 860d18da2ffa769b38385e64f011148ee39d1949..43bfd8dc11e0aa104d83c4c998efc4e50909f202 100644
--- a/include/gpu/GrColor.h
+++ b/include/gpu/GrColor.h
@@ -41,8 +41,7 @@ typedef uint32_t GrColor;
 /**
  *  Pack 4 components (RGBA) into a GrColor int
  */
-static inline GrColor GrColorPackRGBA(unsigned r, unsigned g,
-                                      unsigned b, unsigned a) {
+static inline GrColor GrColorPackRGBA(unsigned r, unsigned g, unsigned b, unsigned a) {
     SkASSERT((uint8_t)r == r);
     SkASSERT((uint8_t)g == g);
     SkASSERT((uint8_t)b == b);
@@ -53,6 +52,17 @@ static inline GrColor GrColorPackRGBA(unsigned r, unsigned g,
             (a << GrColor_SHIFT_A);
 }
 
+/**
+ *  Packs a color with an alpha channel replicated across all four channels.
+ */
+static inline GrColor GrColorPackA4(unsigned a) {
+    SkASSERT((uint8_t)a == a);
+    return  (a << GrColor_SHIFT_R) |
+            (a << GrColor_SHIFT_G) |
+            (a << GrColor_SHIFT_B) |
+            (a << GrColor_SHIFT_A);
+}
+
 // extract a component (byte) from a GrColor int
 
 #define GrColorUnpackR(color)   (((color) >> GrColor_SHIFT_R) & 0xFF)