Work around unused matrix uniform assertion for color filter LUT.

Review URL: http://codereview.appspot.com/6420054/


git-svn-id: http://skia.googlecode.com/svn/trunk@4690 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 1ef52fb..d6e3783 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -515,9 +515,10 @@
         GrTexture* texture = act->set(dev, colorTransformTable, colorSampler);
 
         colorSampler->setCustomStage(SkNEW_ARGS(GrColorTableEffect, (texture)))->unref();
-        colorSampler->setFilter(GrSamplerState::kNearest_Filter);
-        colorSampler->setWrapX(GrSamplerState::kClamp_WrapMode);
-        colorSampler->setWrapY(GrSamplerState::kClamp_WrapMode);
+        // reset() sets the sampler's matrix to I. The custom stage doesn't require the matrix.
+        // The shader generator will omit the matrix if it is I. Once the matrix is moved from the
+        // sampler state to the custom stage this will no longer be necessary.
+        colorSampler->reset(GrSamplerState::kClamp_WrapMode, GrSamplerState::kNearest_Filter);
     } else {
         grPaint->resetColorFilter();
     }