Use RecvMsgWithPid to find real PID for zygote children

content/public/common/child_process_sandbox_support_linux.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_COMMON_CHILD_PROCESS_SANDBOX_SUPPORT_LINUX_H_
 #define CONTENT_PUBLIC_COMMON_CHILD_PROCESS_SANDBOX_SUPPORT_LINUX_H_
 
 #include <stdint.h>
 #include <string>
 
@@ skipping 32 matching lines @@
 //   offset: offset into the table or entire font where loading should start.
 //     The offset must be between 0 and 1 GB - 1.
 //   output: a buffer of size output_length that gets the data.  can be 0, in
 //     which case output_length will be set to the required size in bytes.
 //   output_length: size of output, if it's not 0.
 //
 //   returns: true on success.
 CONTENT_EXPORT bool GetFontTable(int fd, uint32_t table_tag, off_t offset,
                                  uint8_t* output, size_t* output_length);
 
+// Sends a zygote child "ping" message to browser process via socket |fd|.
+// Returns true on success.
+CONTENT_EXPORT bool SendZygoteChildPing(int fd);
+
 };  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_CHILD_PROCESS_SANDBOX_SUPPORT_LINUX_H_