Don't use a global share group for the passthrough command buffer contexts.

gpu/command_buffer/service/service_utils.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/service_utils.h"
 
+#include "base/command_line.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/command_buffer/service/gpu_preferences.h"
+#include "ui/gl/gl_switches.h"
 
 namespace gpu {
 namespace gles2 {
 
 gl::GLContextAttribs GenerateGLContextAttribs(
     const ContextCreationAttribHelper& attribs_helper,
     const GpuPreferences& gpu_preferences) {
   gl::GLContextAttribs attribs;
   attribs.gpu_preference = attribs_helper.gpu_preference;
   if (gpu_preferences.use_passthrough_cmd_decoder) {
     attribs.bind_generates_resource = attribs_helper.bind_generates_resource;
     attribs.webgl_compatibility_context =
         IsWebGLContextType(attribs_helper.context_type);
+
+    // Always use the global texture share group for the passthrough command
+    // decoder
+    attribs.global_texture_share_group = true;
+
+    // Request a specific context version instead of always 3.0
+    if (IsWebGL2OrES3ContextType(attribs_helper.context_type)) {
+      attribs.client_major_es_version = 3;
+      attribs.client_minor_es_version = 0;
+    } else {
+      DCHECK(IsWebGL1OrES2ContextType(attribs_helper.context_type));
+      attribs.client_major_es_version = 2;
+      attribs.client_minor_es_version = 0;
+    }
+  } else {
+    attribs.client_major_es_version = 3;
+    attribs.client_minor_es_version = 0;
   }
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableES3GLContext)) {
+    // Forcefully disable ES3 contexts
+    attribs.client_major_es_version = 2;
+    attribs.client_minor_es_version = 0;
+  }
+
   return attribs;
 }
 
 }  // namespace gles2
 }  // namespace gpu