cc: Add pixel tests for transfer function shaders

cc/output/color_lut_cache.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/color_lut_cache.h"
 
 #include <stdint.h>
 #include <cmath>
 #include <vector>
 
@@ skipping 63 matching lines @@
                  lut_samples * 3);
       for (int i = 0; i < lut_samples; i++) {
         *(lutp++) = *(lutp2++);
         *(lutp++) = *(lutp2++);
         *(lutp++) = *(lutp2++);
         *(lutp++) = alpha;
       }
     }
   }
 
-  unsigned int lut_texture;
+  GLuint previously_bound_texture = 0;
+  GLuint lut_texture = 0;
+  gl_->GetIntegerv(GL_TEXTURE_BINDING_2D,
+                   reinterpret_cast<GLint*>(&previously_bound_texture));
   gl_->GenTextures(1, &lut_texture);
   gl_->BindTexture(GL_TEXTURE_2D, lut_texture);
   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   gl_->TexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, lut_samples,
                   lut_samples * lut_samples, 0, GL_RGBA,
                   sizeof(T) == 1 ? GL_UNSIGNED_BYTE : GL_HALF_FLOAT_OES,
                   lut.data());
+  gl_->BindTexture(GL_TEXTURE_2D, previously_bound_texture);
   return lut_texture;
 }
 
 ColorLUTCache::LUT ColorLUTCache::GetLUT(const gfx::ColorTransform* transform) {
   auto iter = lut_cache_.Get(transform);
   if (iter != lut_cache_.end()) {
     iter->second.last_used_frame = current_frame_;
     return iter->second.lut;
   }
 
@@ skipping 16 matching lines @@
 
 void ColorLUTCache::Swap() {
   current_frame_++;
   while (!lut_cache_.empty() &&
          current_frame_ - lut_cache_.rbegin()->second.last_used_frame >
              kMaxFramesUnused) {
     gl_->DeleteTextures(1, &lut_cache_.rbegin()->second.lut.texture);
     lut_cache_.ShrinkToSize(lut_cache_.size() - 1);
   }
 }