Templatize SkPMFloat to support both 1 and 255 biases.

tests/PMFloatTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPMFloat.h"
 #include "Test.h"
 
 DEF_TEST(SkPMFloat, r) {
     // Test SkPMColor <-> SkPMFloat
     SkPMColor c = SkPreMultiplyColor(0xFFCC9933);
-    SkPMFloat pmf(c);
+    SkPMFloat<1> pmf(c);
     REPORTER_ASSERT(r, SkScalarNearlyEqual(255.0f, 255*pmf.a()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual(204.0f, 255*pmf.r()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual(153.0f, 255*pmf.g()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual( 51.0f, 255*pmf.b()));
     REPORTER_ASSERT(r, c == pmf.round());
 
     // Test rounding.
-    pmf = SkPMFloat(254.5f/255, 203.5f/255, 153.1f/255, 50.8f/255);
+    pmf = SkPMFloat<1>(254.5f/255, 203.5f/255, 153.1f/255, 50.8f/255);
     REPORTER_ASSERT(r, c == pmf.round());
 
-    SkPMFloat clamped(SkPMFloat(510.0f/255, 153.0f/255, 1.0f/255, -0.2f/255).round());
+    SkPMFloat<1> clamped(SkPMFloat<1>(510.0f/255, 153.0f/255, 1.0f/255, -0.2f/255).round());
     REPORTER_ASSERT(r, SkScalarNearlyEqual(255.0f, 255*clamped.a()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual(153.0f, 255*clamped.r()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual(  1.0f, 255*clamped.g()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual(  0.0f, 255*clamped.b()));
 
     // Test SkPMFloat <-> Sk4f conversion.
     Sk4f fs = clamped;
-    SkPMFloat scaled = fs * Sk4f(0.25f);
+    SkPMFloat<1> scaled = fs * Sk4f(0.25f);
     REPORTER_ASSERT(r, SkScalarNearlyEqual(63.75f, 255*scaled.a()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual(38.25f, 255*scaled.r()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual( 0.25f, 255*scaled.g()));
     REPORTER_ASSERT(r, SkScalarNearlyEqual( 0.00f, 255*scaled.b()));
 }