Force input coverage to be only a byte in gpu shaders.

src/gpu/GrAARectRenderer.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAARectRenderer.h"
 #include "GrGpu.h"
 #include "gl/builders/GrGLProgramBuilder.h"
@@ skipping 247 matching lines @@
                                               GrTexture* textures[]) {
     return GrRectEffect::Create();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 namespace {
 extern const GrVertexAttrib gAARectAttribs[] = {
     {kVec2f_GrVertexAttribType,  0,                                 kPosition_GrVertexAttribBinding},
     {kVec4ub_GrVertexAttribType, sizeof(SkPoint),                   kColor_GrVertexAttribBinding},
-    {kVec4ub_GrVertexAttribType, sizeof(SkPoint) + sizeof(SkColor), kCoverage_GrVertexAttribBinding},
+    {kUByte_GrVertexAttribType, sizeof(SkPoint) + sizeof(SkColor), kCoverage_GrVertexAttribBinding},
 };
 
 // Should the coverage be multiplied into the color attrib or use a separate attrib.
 enum CoverageAttribType {
     kUseColor_CoverageAttribType,
     kUseCoverage_CoverageAttribType,
 };
 }
 
 static CoverageAttribType set_rect_attribs(GrDrawState* drawState) {
@@ skipping 631 matching lines @@
     // can't call mapRect for devInside since it calls sort
     combinedMatrix.mapPoints((SkPoint*)&devInside, (const SkPoint*)&rects[1], 2);
 
     if (devInside.isEmpty()) {
         this->fillAARect(target, devOutside, SkMatrix::I(), devOutside);
         return;
     }
 
     this->geometryStrokeAARect(target, devOutside, devOutsideAssist, devInside, true);
 }