Added EGL based GLContext....

app/gfx/gl/gl_implementation_linux.cc

+// Copyright (c) 2010 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 <dlfcn.h>
+
+#include "base/logging.h"
+#include "app/gfx/gl/gl_bindings.h"
+#include "app/gfx/gl/gl_context_stub.h"
+#include "app/gfx/gl/gl_implementation.h"
+
+namespace gfx {
+namespace {
+typedef void* (*GetProcAddressProc)(const char* name);
+
+GLImplementation g_gl_implementation = kGLImplementationNone;
+void* g_shared_library;
+GetProcAddressProc g_get_proc_address;
+}  // namespace anonymous
+
+bool InitializeGLBindings(GLImplementation implementation) {
+  // Prevent reinitialization with a different implementation. Once the gpu
+  // unit tests have initialized with kGLImplementationMock, we don't want to
+  // later switch to another GL implementation.
+  if (g_gl_implementation != kGLImplementationNone)
+    return true;
+
+  switch (implementation) {
+    case kGLImplementationDesktopGL:
+      g_shared_library = dlopen("libGL.so.1", RTLD_LAZY | RTLD_LOCAL);
+      if (!g_shared_library)
+        return false;
+
+      g_gl_implementation = kGLImplementationDesktopGL;
+
+      g_get_proc_address = reinterpret_cast<GetProcAddressProc>(
+          dlsym(g_shared_library, "glXGetProcAddress"));
+      CHECK(g_get_proc_address);
+
+      InitializeGLBindingsGL();
+      InitializeGLBindingsGLX();
+      break;
+
+    case kGLImplementationMockGL:
+      g_get_proc_address = GetMockGLProcAddress;
+      g_gl_implementation = kGLImplementationMockGL;
+      InitializeGLBindingsGL();
+      break;
+
+    default:
+      return false;
+  }
+
+
+  return true;
+}
+
+GLImplementation GetGLImplementation() {
+  return g_gl_implementation;
+}
+
+void* GetGLProcAddress(const char* name) {
+  DCHECK(g_gl_implementation != kGLImplementationNone);
+
+  if (g_get_proc_address) {
+    void* proc = g_get_proc_address(name);
+    if (proc)
+      return proc;
+  }
+
+  if (g_shared_library) {
+    void* proc = dlsym(g_shared_library, name);
+    if (proc)
+      return proc;
+  }
+
+  return NULL;
+}
+
+}  // namespace gfx