Remove task.h and finish base::Bind() migration.

base/base.gypi

 # 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.
 
 {
   'target_defaults': {
     'variables': {
       'base_target': 0,
     },
     'target_conditions': [
@@ skipping 33 matching lines @@
           'base_paths.h',
           'base_paths_android.cc',
           'base_paths_mac.h',
           'base_paths_mac.mm',
           'base_paths_posix.cc',
           'base_paths_win.cc',
           'base_paths_win.h',
           'base_switches.h',
           'basictypes.h',
           'bind.h',
+          'bind_helpers.cc',
           'bind_helpers.h',
           'bind_internal.h',
           'bind_internal_win.h',
           'bits.h',
           'build_time.cc',
           'build_time.h',
           'callback.h',
           'callback_internal.cc',
           'callback_internal.h',
           'cancelable_callback.h',
@@ skipping 233 matching lines @@
           'sys_info_freebsd.cc',
           'sys_info_linux.cc',
           'sys_info_mac.cc',
           'sys_info_openbsd.cc',
           'sys_info_posix.cc',
           'sys_info_win.cc',
           'sys_string_conversions.h',
           'sys_string_conversions_mac.mm',
           'sys_string_conversions_posix.cc',
           'sys_string_conversions_win.cc',
-          'task.cc',
-          'task.h',
           'template_util.h',
           'threading/non_thread_safe.h',
           'threading/non_thread_safe_impl.cc',
           'threading/non_thread_safe_impl.h',
           'threading/platform_thread.h',
           'threading/platform_thread_mac.mm',
           'threading/platform_thread_posix.cc',
           'threading/platform_thread_win.cc',
           'threading/post_task_and_reply_impl.cc',
           'threading/post_task_and_reply_impl.h',
@@ skipping 564 matching lines @@
             'third_party/xdg_mime/xdgmimemagic.c',
             'third_party/xdg_mime/xdgmimemagic.h',
             'third_party/xdg_mime/xdgmimeparent.c',
             'third_party/xdg_mime/xdgmimeparent.h',
           ],
         },
       ],
     }],
   ],
 }