Refactor GL bindings so there is no global GLApi or DriverGL.

ui/gl/gl_egl_api_implementation.cc

 // Copyright (c) 2012 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/gl/gl_egl_api_implementation.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 
 namespace gl {
 
-namespace {
-
-void GL_BINDING_CALL MarshalClearDepthToClearDepthf(GLclampd depth) {
-  glClearDepthf(static_cast<GLclampf>(depth));
-}
-
-void GL_BINDING_CALL MarshalDepthRangeToDepthRangef(GLclampd z_near,
-                                                    GLclampd z_far) {
-  glDepthRangef(static_cast<GLclampf>(z_near), static_cast<GLclampf>(z_far));
-}
-
-}  // namespace
-
-RealEGLApi* g_real_egl;
+RealEGLApi* g_real_egl = nullptr;
+DebugEGLApi* g_debug_egl = nullptr;
 
 void InitializeStaticGLBindingsEGL() {
   g_driver_egl.InitializeStaticBindings();
   if (!g_real_egl) {
     g_real_egl = new RealEGLApi();
   }
   g_real_egl->Initialize(&g_driver_egl);
   g_current_egl_context = g_real_egl;
-
-  // These two functions take single precision float rather than double
-  // precision float parameters in GLES.
-  ::gl::g_driver_gl.fn.glClearDepthFn = MarshalClearDepthToClearDepthf;
-  ::gl::g_driver_gl.fn.glDepthRangeFn = MarshalDepthRangeToDepthRangef;
 }
 
 void InitializeDebugGLBindingsEGL() {
-  g_driver_egl.InitializeDebugBindings();
+  if (!g_debug_egl) {
+    g_debug_egl = new DebugEGLApi(g_real_egl);
+  }
+  g_current_egl_context = g_debug_egl;
 }
 
 void ClearBindingsEGL() {
+  if (g_debug_egl) {
+    delete g_debug_egl;
+    g_debug_egl = NULL;
+  }
   if (g_real_egl) {
     delete g_real_egl;
     g_real_egl = NULL;
   }
   g_current_egl_context = NULL;
   g_driver_egl.ClearBindings();
 }
 
 EGLApi::EGLApi() {
 }
@@ skipping 44 matching lines @@
     if (it == filtered_exts_.end()) {
       it = filtered_exts_.insert(std::make_pair(
           dpy, FilterGLExtensionList(EGLApiBase::eglQueryStringFn(dpy, name),
                                      disabled_exts_))).first;
     }
     return (*it).second.c_str();
   }
   return EGLApiBase::eglQueryStringFn(dpy, name);
 }
 
+DebugEGLApi::DebugEGLApi(EGLApi* egl_api) : egl_api_(egl_api) {}
+
+DebugEGLApi::~DebugEGLApi() {}
+
 TraceEGLApi::~TraceEGLApi() {
 }
 
 bool GetGLWindowSystemBindingInfoEGL(GLWindowSystemBindingInfo* info) {
   EGLDisplay display = eglGetCurrentDisplay();
   const char* vendor = eglQueryString(display, EGL_VENDOR);
   const char* version = eglQueryString(display, EGL_VERSION);
   const char* extensions = eglQueryString(display, EGL_EXTENSIONS);
   *info = GLWindowSystemBindingInfo();
   if (vendor)
     info->vendor = vendor;
   if (version)
     info->version = version;
   if (extensions)
     info->extensions = extensions;
   return true;
 }
 
 }  // namespace gl