Make ChildProcessHost be used through an interface in content/public, instead of by inheritence.

content/content_common.gypi

 # Copyright (c) 2011 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../build/temp_gyp/googleurl.gyp:googleurl',
     '../gpu/gpu.gyp:gpu_ipc',
     '../ipc/ipc.gyp:ipc',
@@ skipping 11 matching lines @@
     '../webkit/support/webkit_support.gyp:fileapi',
   ],
   'include_dirs': [
     '..',
   ],
   'export_dependent_settings': [
     '../base/base.gyp:base',
   ],
   'sources': [
     'public/common/bindings_policy.h',
+    'public/common/child_process_host.h',
     'public/common/child_process_host_delegate.h',
     'public/common/child_process_sandbox_support_linux.h',
     'public/common/content_constants.cc',
     'public/common/content_constants.h',
     'public/common/content_paths.h',
     'public/common/content_restriction.h',
     'public/common/content_switches.cc',
     'public/common/content_switches.h',
     'public/common/dx_diag_node.cc',
     'public/common/dx_diag_node.h',
@@ skipping 33 matching lines @@
     'public/common/url_fetcher_factory.h',
     'public/common/view_type.h',
     'public/common/zygote_fork_delegate_linux.h',
     'common/appcache/appcache_backend_proxy.cc',
     'common/appcache/appcache_backend_proxy.h',
     'common/appcache/appcache_dispatcher.cc',
     'common/appcache/appcache_dispatcher.h',
     'common/appcache_messages.h',
     'common/child_process.cc',
     'common/child_process.h',
-    'common/child_process_host.cc',
-    'common/child_process_host.h',
+    'common/child_process_host_impl.cc',
+    'common/child_process_host_impl.h',
     'common/child_process_messages.h',
     'common/child_process_sandbox_support_impl_linux.cc',
     'common/child_process_sandbox_support_impl_linux.h',
     'common/child_thread.cc',
     'common/child_thread.h',
     'common/child_trace_message_filter.cc',
     'common/child_trace_message_filter.h',
     'common/chrome_application_mac.h',
     'common/chrome_application_mac.mm',
     'common/chrome_descriptors.h',
@@ skipping 221 matching lines @@
       ],
       'link_settings': {
         'libraries': [
           '-lEGL',
           '-lGLESv2',
         ],
       },
     }],
   ],
 }