Refactor GrGLUniformManager::UniformHandle to initialize itself by default

src/gpu/gl/GrGLEffectMatrix.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 "GrGLEffectMatrix.h"
 #include "GrDrawEffect.h"
 #include "GrTexture.h"
@@ skipping 171 matching lines @@
     }
     if (NULL != vsVaryingType) {
         *vsVaryingType = varyingType;
     }
 }
 
 void GrGLEffectMatrix::setData(const GrGLUniformManager& uniformManager,
                                const SkMatrix& matrix,
                                const GrDrawEffect& drawEffect,
                                const GrTexture* texture) {
-    GrAssert((GrGLUniformManager::kInvalidUniformHandle == fUni) ==
-             (kVoid_GrSLType == fUniType));
+    GrAssert(fUni.isValid() != (kVoid_GrSLType == fUniType));
     const SkMatrix& coordChangeMatrix = GrEffect::kLocal_CoordsType == fCoordsType ?
                                             drawEffect.getCoordChangeMatrix() :
                                             SkMatrix::I();
     switch (fUniType) {
         case kVoid_GrSLType:
             GrAssert(matrix.isIdentity());
             GrAssert(coordChangeMatrix.isIdentity());
             GrAssert(NULL == texture || kTopLeft_GrSurfaceOrigin == texture->origin());
             return;
         case kVec2f_GrSLType: {
@@ skipping 25 matching lines @@
             if (!fPrevMatrix.cheapEqualTo(combined)) {
                 uniformManager.setSkMatrix(fUni, combined);
                 fPrevMatrix = combined;
             }
             break;
         }
         default:
             GrCrash("Unexpected uniform type.");
     }
 }