Fix gcc 4.6 warnings in gpu.

gpu/command_buffer/client/gles2_implementation_unittest.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.
 
 // Tests for GLES2Implementation.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2ext.h>
 #include "gpu/command_buffer/client/client_test_helper.h"
@@ skipping 2020 matching lines @@
       kSubImageWidth, 2, kFormat, kType, kPixelStoreUnpackAlignment,
       &sub_2_high_size));
 
   ExpectedMemoryInfo mem1 = GetExpectedMemory(sub_2_high_size);
   ExpectedMemoryInfo mem2 = GetExpectedMemory(sub_2_high_size);
 
   Cmds expected;
   expected.pixel_store_i1.Init(GL_UNPACK_ALIGNMENT, kPixelStoreUnpackAlignment);
   expected.tex_image_2d.Init(
       kTarget, kLevel, kFormat, kTextureWidth, kTextureHeight, kBorder, kFormat,
-      kType, 0, NULL);
+      kType, 0, 0);
   expected.tex_sub_image_2d1.Init(kTarget, kLevel, kSubImageXOffset,
       kSubImageYOffset + 2, kSubImageWidth, 2, kFormat, kType,
       mem1.id, mem1.offset, false);
   expected.set_token1.Init(GetNextToken());
   expected.tex_sub_image_2d2.Init(kTarget, kLevel, kSubImageXOffset,
       kSubImageYOffset, kSubImageWidth , 2, kFormat, kType,
       mem2.id, mem2.offset, false);
   expected.set_token2.Init(GetNextToken());
 
   gl_->PixelStorei(GL_UNPACK_ALIGNMENT, kPixelStoreUnpackAlignment);
@@ skipping 248 matching lines @@
   gl_->BufferData(GL_ARRAY_BUFFER, arraysize(buf), buf, GL_DYNAMIC_DRAW);
   EXPECT_EQ(0, memcmp(&expected, commands_, sizeof(expected)));
 }
 
 #include "gpu/command_buffer/client/gles2_implementation_unittest_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu