Send coverage VA as floats instead of bytes

src/gpu/gl/GrGLProgram.cpp

Index: src/gpu/gl/GrGLProgram.cpp
diff --git a/src/gpu/gl/GrGLProgram.cpp b/src/gpu/gl/GrGLProgram.cpp
index 319dcceff19c53fa45fb08d0ab557767363d1d66..3456a424d0ee76f76c35cdecef30ae9a4fe52e0b 100644
--- a/src/gpu/gl/GrGLProgram.cpp
+++ b/src/gpu/gl/GrGLProgram.cpp
@@ -232,8 +232,7 @@ void GrGLProgram::setCoverage(const GrOptDrawState& optState, uint8_t coverage)
         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;
             }