gpu: support immutable texture on Linux Mesa driver and GLES3.

gpu/command_buffer/service/feature_info.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/feature_info.h"
 
 #include <set>
 
 #include "base/command_line.h"
 #include "base/macros.h"
@@ skipping 673 matching lines @@
     validators_.pixel_store.AddValue(GL_PACK_REVERSE_ROW_ORDER_ANGLE);
     validators_.g_l_state.AddValue(GL_PACK_REVERSE_ROW_ORDER_ANGLE);
   }
 
   if (extensions.Contains("GL_ANGLE_texture_usage")) {
     feature_flags_.angle_texture_usage = true;
     AddExtensionString("GL_ANGLE_texture_usage");
     validators_.texture_parameter.AddValue(GL_TEXTURE_USAGE_ANGLE);
   }
 
-  if (extensions.Contains("GL_EXT_texture_storage")) {
+  if (extensions.Contains("GL_EXT_texture_storage") ||
+      extensions.Contains("GL_ARB_texture_storage") ||
+      is_es3) {
     feature_flags_.ext_texture_storage = true;
     AddExtensionString("GL_EXT_texture_storage");
     validators_.texture_parameter.AddValue(GL_TEXTURE_IMMUTABLE_FORMAT_EXT);
     if (enable_texture_format_bgra8888)
         validators_.texture_internal_format_storage.AddValue(GL_BGRA8_EXT);
     if (enable_texture_float) {
         validators_.texture_internal_format_storage.AddValue(GL_RGBA32F_EXT);
         validators_.texture_internal_format_storage.AddValue(GL_RGB32F_EXT);
         validators_.texture_internal_format_storage.AddValue(GL_ALPHA32F_EXT);
         validators_.texture_internal_format_storage.AddValue(
@@ skipping 139 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu