Send coverage VA as floats instead of bytes

src/gpu/gl/GrGLProgram.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLProgram.h"
 
 #include "GrAllocator.h"
@@ skipping 214 matching lines @@
 
 void GrGLProgram::setCoverage(const GrOptDrawState& optState, uint8_t coverage) {
     const GrProgramDesc::KeyHeader& header = fDesc.header();
     switch (header.fCoverageInput) {
         case GrProgramDesc::kAttribute_ColorInput:
             // Attribute case is handled in GrGpuGL::setupGeometry
             break;
         case GrProgramDesc::kUniform_ColorInput:
             if (fCoverage != coverage) {
                 // OpenGL ES doesn't support unsigned byte varieties of glUniform
-                static const float ONE_OVER_255 = 1.f / 255.f;
-                GrGLfloat c = coverage * ONE_OVER_255;
+                GrGLfloat c = GrNormalizeByteToFloat(coverage);
                 fProgramDataManager.set1f(fBuiltinUniformHandles.fCoverageUni, c);
                 fCoverage = coverage;
             }
             break;
         case GrProgramDesc::kAllOnes_ColorInput:
             // Handled by shader creation
             break;
         default:
             SkFAIL("Unexpected coverage type.");
     }
@@ skipping 131 matching lines @@
     for (int t = 0; t < numTransforms; ++t) {
         const SkMatrix& transform = get_transform_matrix(proc, false, t);
         GrGLPathRendering::PathTexGenComponents components =
                 GrGLPathRendering::kST_PathTexGenComponents;
         if (proc.isPerspectiveCoordTransform(t, false)) {
             components = GrGLPathRendering::kSTR_PathTexGenComponents;
         }
         fGpu->glPathRendering()->enablePathTexGen(texCoordIndex++, components, transform);
     }
 }