use pinned value during lerp for vertical gradients

gm/gradients.cpp

Index: gm/gradients.cpp
diff --git a/gm/gradients.cpp b/gm/gradients.cpp
index 92e22eebefd1a64d8e5864f6c4b0c8fd62ef5685..9c4d6211b7d85b72457bf53c2a78364c8a59df58 100644
--- a/gm/gradients.cpp
+++ b/gm/gradients.cpp
@@ -610,19 +610,20 @@ protected:
             SkPoint pts[2];
             SkScalar pos[kStopCount];
         } configs[] = {
-            { { SkPoint::Make(0, 0), SkPoint::Make(10, 0) }, { 0, 0.999999f,    1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(10, 0) }, { 0, 0.000001f,    1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(10, 0) }, { 0, 0.999999999f, 1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(10, 0) }, { 0, 0.000000001f, 1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(0, 10) }, { 0, 0.999999f,    1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(0, 10) }, { 0, 0.000001f,    1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(0, 10) }, { 0, 0.999999999f, 1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(0, 10) }, { 0, 0.000000001f, 1 }},
-
-            { { SkPoint::Make(0, 0), SkPoint::Make(0.00001f, 0) } , { 0, 0.5f, 1 }},
-            { { SkPoint::Make(9.99999f, 0), SkPoint::Make(10, 0) }, { 0, 0.5f, 1 }},
-            { { SkPoint::Make(0, 0), SkPoint::Make(0, 0.00001f) },  { 0, 0.5f, 1 }},
-            { { SkPoint::Make(0, 9.99999f), SkPoint::Make(0, 10) }, { 0, 0.5f, 1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(10, 0) },       { 0, 0.999999f,    1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(10, 0) },       { 0, 0.000001f,    1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(10, 0) },       { 0, 0.999999999f, 1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(10, 0) },       { 0, 0.000000001f, 1 }},
+
+            { { SkPoint::Make(0, 0),        SkPoint::Make(0, 10) },       { 0, 0.999999f,    1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(0, 10) },       { 0, 0.000001f,    1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(0, 10) },       { 0, 0.999999999f, 1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(0, 10) },       { 0, 0.000000001f, 1 }},
+
+            { { SkPoint::Make(0, 0),        SkPoint::Make(0.00001f, 0) }, { 0, 0.5f, 1 }},
+            { { SkPoint::Make(9.99999f, 0), SkPoint::Make(10, 0) },       { 0, 0.5f, 1 }},
+            { { SkPoint::Make(0, 0),        SkPoint::Make(0, 0.00001f) }, { 0, 0.5f, 1 }},
+            { { SkPoint::Make(0, 9.99999f), SkPoint::Make(0, 10) },       { 0, 0.5f, 1 }},
         };
 
         SkPaint paint;