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

gpu/command_buffer/common/gles2_cmd_utils.h

 // 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.
 
 // This file is here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 #define GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 
@@ skipping 290 matching lines @@
 };
 
 enum ContextType {
   CONTEXT_TYPE_WEBGL1,
   CONTEXT_TYPE_WEBGL2,
   CONTEXT_TYPE_OPENGLES2,
   CONTEXT_TYPE_OPENGLES3,
   CONTEXT_TYPE_LAST = CONTEXT_TYPE_OPENGLES3
 };
 GLES2_UTILS_EXPORT bool IsWebGLContextType(ContextType context_type);
+GLES2_UTILS_EXPORT bool IsWebGL1OrES2ContextType(ContextType context_type);
+GLES2_UTILS_EXPORT bool IsWebGL2OrES3ContextType(ContextType context_type);
 
 struct GLES2_UTILS_EXPORT ContextCreationAttribHelper {
   ContextCreationAttribHelper();
   ContextCreationAttribHelper(const ContextCreationAttribHelper& other);
 
   bool Parse(const std::vector<int32_t>& attribs);
 
   gfx::Size offscreen_framebuffer_size;
   gl::GpuPreference gpu_preference;
   // -1 if invalid or unspecified.
@@ skipping 12 matching lines @@
   bool should_use_native_gmb_for_backbuffer;
 
   ContextType context_type;
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_