Allow GLSurface to indicate that it supports a specific extension.

ui/gfx/gl/gl_surface_glx.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.
 
 extern "C" {
 #include <X11/Xlib.h>
 }
 
 #include "ui/gfx/gl/gl_surface_glx.h"
 
@@ skipping 55 matching lines @@
   }
 
   g_glx_extensions = glXQueryExtensionsString(g_display, 0);
   g_glx_create_context_robustness_supported =
       HasGLXExtension("GLX_ARB_create_context_robustness");
 
   initialized = true;
   return true;
 }
 
+// static
 const char* GLSurfaceGLX::GetGLXExtensions() {
   return g_glx_extensions;
 }
 
+// static
 bool GLSurfaceGLX::HasGLXExtension(const char* name) {
   DCHECK(name);
   const char* c_extensions = GetGLXExtensions();
   if (!c_extensions)
     return false;
   std::string extensions(c_extensions);
   extensions += " ";
 
   std::string delimited_name(name);
   delimited_name += " ";
 
   return extensions.find(delimited_name) != std::string::npos;
 }
 
+// static
 bool GLSurfaceGLX::IsCreateContextRobustnessSupported() {
   return g_glx_create_context_robustness_supported;
 }
 
 void* GLSurfaceGLX::GetDisplay() {
   return g_display;
 }
 
 NativeViewGLSurfaceGLX::NativeViewGLSurfaceGLX(gfx::PluginWindowHandle window)
   : window_(window),
@@ skipping 31 matching lines @@
     LOG(ERROR) << "XGetWindowAttributes failed for window " << window_ << ".";
     return gfx::Size();
   }
   return gfx::Size(attributes.width, attributes.height);
 }
 
 void* NativeViewGLSurfaceGLX::GetHandle() {
   return reinterpret_cast<void*>(window_);
 }
 
+std::string NativeViewGLSurfaceGLX::GetExtensions() {
+  std::string extensions = GLSurface::GetExtensions();
+  if (g_GLX_MESA_copy_sub_buffer) {
+    extensions += extensions.empty() ? "" : " ";
+    extensions += "GL_CHROMIUM_post_sub_buffer";
+  }
+  return extensions;
+}
+
 void* NativeViewGLSurfaceGLX::GetConfig() {
   if (!config_) {
     // This code path is expensive, but we only take it when
     // attempting to use GLX_ARB_create_context_robustness, in which
     // case we need a GLXFBConfig for the window in order to create a
     // context for it.
     //
     // TODO(kbr): this is not a reliable code path. On platforms which
     // support it, we should use glXChooseFBConfig in the browser
     // process to choose the FBConfig and from there the X Visual to
@@ skipping 41 matching lines @@
       }
     }
     if (found) {
       config_ = configs.get()[i];
     }
   }
 
   return config_;
 }
 
-bool NativeViewGLSurfaceGLX::SupportsPostSubBuffer() {
-  return g_GLX_MESA_copy_sub_buffer;
-}
-
 bool NativeViewGLSurfaceGLX::PostSubBuffer(
     int x, int y, int width, int height) {
-  DCHECK(SupportsPostSubBuffer());
+  DCHECK(g_GLX_MESA_copy_sub_buffer);
   glXCopySubBufferMESA(g_display, window_, x, y, width, height);
   return true;
 }
 
 PbufferGLSurfaceGLX::PbufferGLSurfaceGLX(const gfx::Size& size)
   : size_(size),
     config_(NULL),
     pbuffer_(0) {
 }
 
@@ skipping 74 matching lines @@
 
 void* PbufferGLSurfaceGLX::GetHandle() {
   return reinterpret_cast<void*>(pbuffer_);
 }
 
 void* PbufferGLSurfaceGLX::GetConfig() {
   return config_;
 }
 
 }  // namespace gfx