expand unitests for color4f

include/core/SkColor.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkColor_DEFINED
 #define SkColor_DEFINED
 
@@ skipping 151 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 /*
  *  The float values are 0...1 premultiplied
  */
 struct SkPM4f {
     float fVec[4];
 
     float a() const { return fVec[SK_A32_SHIFT/8]; }
+
+    static SkPM4f FromPMColor(SkPMColor);
 };
 
 /*
  *  The float values are 0...1 unpremultiplied
  */
 struct SkColor4f {
     float fA;
     float fR;
     float fG;
     float fB;
@@ skipping 12 matching lines @@
     static SkColor4f FromColor(SkColor);
 
     SkColor4f pin() const {
         return Pin(fA, fR, fG, fB);
     }
 
     SkPM4f premul() const;
 };
 
 #endif