Revert of gl programs rewrite

src/effects/SkColorFilters.cpp

Index: src/effects/SkColorFilters.cpp
diff --git a/src/effects/SkColorFilters.cpp b/src/effects/SkColorFilters.cpp
index 8e10d73a0eea9239be37b36f682927d9ceeff7a8..ba62817f568beb7cee92aba584f5a2276e5e2442 100644
--- a/src/effects/SkColorFilters.cpp
+++ b/src/effects/SkColorFilters.cpp
@@ -406,13 +406,7 @@
     while (SkXfermode::kDst_Mode == mode) {
         mode = static_cast<SkXfermode::Mode>(rand->nextRangeU(0, SkXfermode::kLastCoeffMode));
     }
-
-    // pick a random premul color
-    uint8_t alpha = rand->nextULessThan(256);
-    GrColor color = GrColorPackRGBA(rand->nextRangeU(0, alpha),
-                                    rand->nextRangeU(0, alpha),
-                                    rand->nextRangeU(0, alpha),
-                                    alpha);
+    GrColor color = rand->nextU();
     return ModeColorFilterEffect::Create(color, mode);
 }