Update from https://crrev.com/312398

base/process/process.h

 // 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.
 
 #ifndef BASE_PROCESS_PROCESS_PROCESS_H_
 #define BASE_PROCESS_PROCESS_PROCESS_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/move.h"
@@ skipping 31 matching lines @@
 
   // The destructor does not terminate the process.
   ~Process() {}
 
   // Move operator= for C++03 move emulation of this type.
   Process& operator=(RValue other);
 
   // Returns an object for the current process.
   static Process Current();
 
+  // Returns a Process for the given |pid|. On Windows the handle is opened
+  // with more access rights and must only be used by trusted code (can read the
+  // address space and duplicate handles).
+  static Process OpenWithExtraPriviles(ProcessId pid);
+
   // Creates an object from a |handle| owned by someone else.
   // Don't use this for new code. It is only intended to ease the migration to
   // a strict ownership model.
   // TODO(rvargas) crbug.com/417532: Remove this code.
   static Process DeprecatedGetProcessFromHandle(ProcessHandle handle);
 
   // Returns true if processes can be backgrounded.
   static bool CanBackgroundProcesses();
 
   // Returns true if this objects represents a valid process.
@@ skipping 43 matching lines @@
 
  private:
 #if defined(OS_WIN)
   bool is_current_process_;
   win::ScopedHandle process_;
 #else
   ProcessHandle process_;
 #endif
 };
 
+#if defined(OS_LINUX)
+// A wrapper for clone with fork-like behavior, meaning that it returns the
+// child's pid in the parent and 0 in the child. |flags|, |ptid|, and |ctid| are
+// as in the clone system call (the CLONE_VM flag is not supported).
+//
+// This function uses the libc clone wrapper (which updates libc's pid cache)
+// internally, so callers may expect things like getpid() to work correctly
+// after in both the child and parent. An exception is when this code is run
+// under Valgrind. Valgrind does not support the libc clone wrapper, so the libc
+// pid cache may be incorrect after this function is called under Valgrind.
+//
+// As with fork(), callers should be extremely careful when calling this while
+// multiple threads are running, since at the time the fork happened, the
+// threads could have been in any state (potentially holding locks, etc.).
+// Callers should most likely call execve() in the child soon after calling
+// this.
+BASE_EXPORT pid_t ForkWithFlags(unsigned long flags, pid_t* ptid, pid_t* ctid);
+#endif
+
 }  // namespace base
 
 #endif  // BASE_PROCESS_PROCESS_PROCESS_H_