Use the extensions generated by FeatureInfo in the passthrough cmd decoder.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

 // Copyright (c) 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 "gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h"
 
 #include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "ui/gl/gl_version_info.h"
 
@@ skipping 185 matching lines @@
   if (feature_info_->IsWebGL2OrES3Context()) {
     bound_textures_[GL_TEXTURE_2D_ARRAY].resize(num_texture_units, 0);
     bound_textures_[GL_TEXTURE_3D].resize(num_texture_units, 0);
   }
 
   if (group_->gpu_preferences().enable_gpu_driver_debug_logging &&
       feature_info_->feature_flags().khr_debug) {
     InitializeGLDebugLogging();
   }
 
-  emulated_extensions_.push_back("GL_CHROMIUM_async_pixel_transfers");
-  emulated_extensions_.push_back("GL_CHROMIUM_command_buffer_query");
-  emulated_extensions_.push_back("GL_CHROMIUM_command_buffer_latency_query");
-  emulated_extensions_.push_back("GL_CHROMIUM_get_error_query");
-  emulated_extensions_.push_back("GL_CHROMIUM_lose_context");
-  emulated_extensions_.push_back("GL_CHROMIUM_pixel_transfer_buffer_object");
-  emulated_extensions_.push_back("GL_CHROMIUM_resource_safe");
-  emulated_extensions_.push_back("GL_CHROMIUM_strict_attribs");
-  emulated_extensions_.push_back("GL_CHROMIUM_texture_mailbox");
-  emulated_extensions_.push_back("GL_CHROMIUM_trace_marker");
-  BuildExtensionsString();
-
   set_initialized();
   return true;
 }
 
 void GLES2DecoderPassthroughImpl::Destroy(bool have_context) {
   image_manager_.reset();
 
   DeleteServiceObjects(
       &framebuffer_id_map_, have_context,
       [](GLuint framebuffer) { glDeleteFramebuffersEXT(1, &framebuffer); });
@@ skipping 346 matching lines @@
 error::Error GLES2DecoderPassthroughImpl::PatchGetNumericResults(GLenum pname,
                                                                  GLsizei length,
                                                                  T* params) {
   // Likely a gl error if no parameters were returned
   if (length < 1) {
     return error::kNoError;
   }
 
   switch (pname) {
     case GL_NUM_EXTENSIONS:
-      *params = *params + static_cast<T>(emulated_extensions_.size());
+      // Currently handled on the client side.
+      params[0] = 0;
       break;
 
     case GL_TEXTURE_BINDING_2D:
     case GL_TEXTURE_BINDING_CUBE_MAP:
     case GL_TEXTURE_BINDING_2D_ARRAY:
     case GL_TEXTURE_BINDING_3D:
       if (!GetClientID(&resources_->texture_id_map, *params, params)) {
         return error::kInvalidArguments;
       }
       break;
@@ skipping 109 matching lines @@
       }
     } break;
 
     default:
       break;
   }
 
   return error::kNoError;
 }
 
-void GLES2DecoderPassthroughImpl::BuildExtensionsString() {
-  std::ostringstream combined_string_stream;
-  combined_string_stream << reinterpret_cast<const char*>(
-                                glGetString(GL_EXTENSIONS))
-                         << " ";
-  std::copy(emulated_extensions_.begin(), emulated_extensions_.end(),
-            std::ostream_iterator<std::string>(combined_string_stream, " "));
-  extension_string_ = combined_string_stream.str();
-}
-
 void GLES2DecoderPassthroughImpl::InsertError(GLenum error,
                                               const std::string&) {
   // Message ignored for now
   errors_.insert(error);
 }
 
 GLenum GLES2DecoderPassthroughImpl::PopError() {
   GLenum error = GL_NO_ERROR;
   if (!errors_.empty()) {
     error = *errors_.begin();
@@ skipping 127 matching lines @@
   }, /* NOLINT */
 
 const GLES2DecoderPassthroughImpl::CommandInfo
     GLES2DecoderPassthroughImpl::command_info[] = {
         GLES2_COMMAND_LIST(GLES2_CMD_OP)};
 
 #undef GLES2_CMD_OP
 
 }  // namespace gles2
 }  // namespace gpu