Check bounds before casting float to integer in SamplePatch.cpp and SkBlurMaskFilter::CreateEmboss.

BUG=skia:4632
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1693013002

Review URL: https://codereview.chromium.org/1693013002
diff --git a/samplecode/SamplePatch.cpp b/samplecode/SamplePatch.cpp
index 92bb17c..5347b01 100644
--- a/samplecode/SamplePatch.cpp
+++ b/samplecode/SamplePatch.cpp
@@ -109,20 +109,8 @@
     pt->set(x, y);
 }
 
-static int ScalarTo255(SkScalar v) {
-    int scale = SkScalarToFixed(v) >> 8;
-    if (scale < 0) {
-        scale = 0;
-    } else if (scale > 255) {
-        scale = 255;
-    }
-    return scale;
-}
-
 static SkColor make_color(SkScalar s, SkScalar t) {
-    int cs = ScalarTo255(s);
-    int ct = ScalarTo255(t);
-    return SkColorSetARGB(0xFF, cs, 0, 0) + SkColorSetARGB(0, 0, ct, 0);
+    return SkColorSetARGB(0xFF, SkUnitScalarClampToByte(s), SkUnitScalarClampToByte(t), 0);
 }
 
 void Patch::draw(SkCanvas* canvas, const SkPaint& paint, int nu, int nv,