Allow GLSurface to indicate that it supports a specific extension.

ui/gfx/gl/gl_context.cc

 // Copyright (c) 2011 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 <string>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/threading/thread_local.h"
@@ skipping 21 matching lines @@
 
 GLContext::~GLContext() {
   share_group_->RemoveContext(this);
   if (GetCurrent() == this) {
     SetCurrent(NULL, NULL);
   }
 }
 
 std::string GLContext::GetExtensions() {
   DCHECK(IsCurrent(NULL));
-  const char* ext = reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
-  return std::string(ext ? ext : "");
+
+  std::string extensions;
+  if (GLSurface::GetCurrent()) {
+    extensions = GLSurface::GetCurrent()->GetExtensions();
+  }
+
+  const char* gl_ext = reinterpret_cast<const char*>(
+      glGetString(GL_EXTENSIONS));
+  if (gl_ext) {
+    extensions += (!extensions.empty() && gl_ext[0]) ? " " : "";
+    extensions += gl_ext;
+  }
+
+  return extensions;
 }
 
 bool GLContext::HasExtension(const char* name) {
   std::string extensions = GetExtensions();
   extensions += " ";
 
   std::string delimited_name(name);
   delimited_name += " ";
 
   return extensions.find(delimited_name) != std::string::npos;
@@ skipping 38 matching lines @@
   static bool initialized = false;
   if (initialized)
     return initialized;
   initialized = InitializeGLExtensionBindings(GetGLImplementation(), this);
   if (!initialized)
     LOG(ERROR) << "Could not initialize extension bindings.";
   return initialized;
 }
 
 }  // namespace gfx