Remove chromium extensions obsoleted by gpu::Capabilities

Remove these extensions that do not guard any new gl functions:
GL_CHROMIUM_front_buffer_cached
GL_CHROMIUM_fast_NPOT_MO8_textures

BUG=285390
NOTRY=true

Review URL: https://codereview.chromium.org/112343010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244376 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index d76fec6..231ea24 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -2575,13 +2575,7 @@
   caps.iosurface = true;
 #endif
 
-  // TODO(boliu): Expose this directly from GLSurface.
-  std::vector<std::string> extension_list;
-  base::SplitString(surface_->GetExtensions(), ' ', &extension_list);
-  std::set<std::string> extension_set(extension_list.begin(),
-                                      extension_list.end());
-  caps.post_sub_buffer =
-      extension_set.count("GL_CHROMIUM_post_sub_buffer") > 0;
+  caps.post_sub_buffer = surface_->HasExtension("GL_CHROMIUM_post_sub_buffer");
 
   return caps;
 }