Split GL binding init into core and extension part

ui/gfx/gl/gl_implementation.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 "ui/gfx/gl/gl_implementation.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/at_exit.h"
@@ skipping 23 matching lines @@
 void CleanupNativeLibraries(void* unused) {
   if (g_libraries) {
     for (LibraryArray::iterator it = g_libraries->begin();
          it != g_libraries->end(); ++it) {
       base::UnloadNativeLibrary(*it);
     }
     delete g_libraries;
     g_libraries = NULL;
   }
 }
+
+bool ExportsCoreFunctionsFromGetProcAddress(GLImplementation implementation) {
+  switch (GetGLImplementation()) {
+    case kGLImplementationDesktopGL:
+    case kGLImplementationOSMesaGL:
+    case kGLImplementationMockGL:
+      return true;
+    case kGLImplementationEGLGLES2:
+      return false;
+    default:
+      NOTREACHED();
+      return true;
+  }
+}
+
 }
 
 GLImplementation GetNamedGLImplementation(const std::string& name) {
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kGLImplementationNamePairs); ++i) {
     if (name == kGLImplementationNamePairs[i].name)
       return kGLImplementationNamePairs[i].implementation;
   }
 
   return kGLImplementationNone;
 }
@@ skipping 76 matching lines @@
   }
 
   g_libraries->push_back(library);
 }
 
 void SetGLGetProcAddressProc(GLGetProcAddressProc proc) {
   DCHECK(proc);
   g_get_proc_address = proc;
 }
 
-void* GetGLProcAddress(const char* name) {
+void* GetGLCoreProcAddress(const char* name) {
   DCHECK(g_gl_implementation != kGLImplementationNone);
 
   if (g_libraries) {
     for (size_t i = 0; i < g_libraries->size(); ++i) {
       void* proc = base::GetFunctionPointerFromNativeLibrary((*g_libraries)[i],
                                                              name);
       if (proc)
         return proc;
     }
   }
-
-  if (g_get_proc_address) {
+  if (ExportsCoreFunctionsFromGetProcAddress(g_gl_implementation) &&
+      g_get_proc_address) {
     void* proc = g_get_proc_address(name);
     if (proc)
       return proc;
   }
 
   return NULL;
 }
 
+void* GetGLProcAddress(const char* name) {
+  DCHECK(g_gl_implementation != kGLImplementationNone);
+
+  void* proc = GetGLCoreProcAddress(name);
+  if (!proc && g_get_proc_address) {
+    proc = g_get_proc_address(name);
+    if (proc)
+      return proc;
+  }
+
+  return proc;
+}
+
 }  // namespace gfx