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

ui/gl/gl_image_memory.cc

 // Copyright 2014 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_image_memory.h"
 
 #include <stdint.h>
 
 #include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
@@ skipping 296 matching lines @@
                           },
                           data_format, data_type, data_row_length);
     case gfx::BufferFormat::RGBA_4444:
     case gfx::BufferFormat::RGBA_8888:
     case gfx::BufferFormat::BGRA_8888:
     case gfx::BufferFormat::R_8:
     case gfx::BufferFormat::RG_88: {
       size_t gles2_data_stride =
           RowSizeForBufferFormat(size.width(), format, 0);
       if (stride == gles2_data_stride ||
-          g_driver_gl.ext.b_GL_EXT_unpack_subimage)
+          g_current_gl_driver->ext.b_GL_EXT_unpack_subimage)
         return nullptr;  // No data conversion needed
 
       std::unique_ptr<uint8_t[]> gles2_data(
           new uint8_t[gles2_data_stride * size.height()]);
       for (int y = 0; y < size.height(); ++y) {
         memcpy(&gles2_data[y * gles2_data_stride], &data[y * stride],
                gles2_data_stride);
       }
       *data_row_length = size.width();
       return gles2_data;
@@ skipping 162 matching lines @@
   return false;
 }
 
 // static
 unsigned GLImageMemory::GetInternalFormatForTesting(gfx::BufferFormat format) {
   DCHECK(ValidFormat(format));
   return TextureFormat(format);
 }
 
 }  // namespace gl