Reset PIXEL_UNPACK_BUFFER at texture manager initialization time

gpu/command_buffer/service/texture_manager.cc

 // Copyright (c) 2012 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 "gpu/command_buffer/service/texture_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 1763 matching lines @@
       num_images_(0),
       texture_count_(0),
       have_context_(true),
       current_service_id_generation_(0) {
   for (int ii = 0; ii < kNumDefaultTextures; ++ii) {
     black_texture_ids_[ii] = 0;
   }
 }
 
 bool TextureManager::Initialize() {
+  // Reset PIXEL_UNPACK_BUFFER to avoid unrelated GL error on some GL drivers.
+  if (feature_info_->gl_version_info().is_es3_capable) {

[qiankun, 2016/09/09 09:52:48]

Using this other than feature_info_->IsES3Capable() here because it's difficult
to check feature_info_->IsES3Capable() in gpu_unittests when implementing
SetupTextureManagerInitExpectations in test_helper.cc. I took whole day but
didn't find a good solution. If you have better method, please tell me.  Thanks.

[Zhenyao Mo, 2016/09/09 15:17:08]

You can use feature_info_->IsES3Capable() here and use
gl_version_info.is_es3_capable in the test.  There are some slight difference
between the two, but as far as it doesn't affect the tests, I feel it's no big
deal.

Or is this difference causing tests to fail?

[qiankun, 2016/09/09 18:16:26]

For some test cases, if --enable-unsafe-es3-apis is set,
gl_version_info.is_es3_capable and feature_info_->IsES3Capable() are different.
This makes EXPECT_CALL check fail.

+    glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
+  }
+
   // TODO(gman): The default textures have to be real textures, not the 0
   // texture because we simulate non shared resources on top of shared
   // resources and all contexts that share resource share the same default
   // texture.
   default_textures_[kTexture2D] = CreateDefaultAndBlackTextures(
       GL_TEXTURE_2D, &black_texture_ids_[kTexture2D]);
   default_textures_[kCubeMap] = CreateDefaultAndBlackTextures(
       GL_TEXTURE_CUBE_MAP, &black_texture_ids_[kCubeMap]);
 
   if (feature_info_->IsES3Enabled()) {
@@ skipping 1601 matching lines @@
 uint32_t TextureManager::GetServiceIdGeneration() const {
   return current_service_id_generation_;
 }
 
 void TextureManager::IncrementServiceIdGeneration() {
   current_service_id_generation_++;
 }
 
 }  // namespace gles2
 }  // namespace gpu