Add GM that tests GrTextureDomain and fix bug where kDecal_Mode gets incorrectly ignored.

src/gpu/effects/GrTextureDomain.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 "GrTextureDomain.h"
 #include "GrSimpleTextureEffect.h"
 #include "GrTBackendEffectFactory.h"
 #include "gl/GrGLEffect.h"
 #include "SkFloatingPoint.h"
 
 
 GrTextureDomain::GrTextureDomain(const SkRect& domain, Mode mode, int index)
     : fIndex(index) {
 
     static const SkRect kFullRect = {0, 0, SK_Scalar1, SK_Scalar1};
-    if (domain.contains(kFullRect)) {
+    if (domain.contains(kFullRect) && kClamp_Mode == mode) {
         fMode = kIgnore_Mode;
     } else {
         fMode = mode;
     }
 
     if (fMode != kIgnore_Mode) {
         // We don't currently handle domains that are empty or don't intersect the texture.
         // It is OK if the domain rect is a line or point, but it should not be inverted. We do not
         // handle rects that do not intersect the [0..1]x[0..1] rect.
         SkASSERT(domain.fLeft <= domain.fRight);
@@ skipping 241 matching lines @@
     const SkMatrix& matrix = GrEffectUnitTest::TestMatrix(random);
     bool bilerp = random->nextBool();
     GrCoordSet coords = random->nextBool() ? kLocal_GrCoordSet : kPosition_GrCoordSet;
     return GrTextureDomainEffect::Create(textures[texIdx],
                                          matrix,
                                          domain,
                                          mode,
                                          bilerp ? GrTextureParams::kBilerp_FilterMode : GrTextureParams::kNone_FilterMode,
                                          coords);
 }