Linux: Enable metrics_service_uitest.cc. Take 2.

chrome/browser/zygote_host_linux.h

 // Copyright (c) 2009 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 CHROME_BROWSER_ZYGOTE_HOST_LINUX_H_
 #define CHROME_BROWSER_ZYGOTE_HOST_LINUX_H_
 
 #include <string>
 #include <vector>
 
 #include "base/global_descriptors_posix.h"
-#include "base/singleton.h"
+#include "base/process.h"
+
+template<typename Type>
+struct DefaultSingletonTraits;
 
 // http://code.google.com/p/chromium/wiki/LinuxZygote
 
 // The zygote host is the interface, in the browser process, to the zygote
 // process.
 class ZygoteHost {
  public:
   ~ZygoteHost();
 
   pid_t ForkRenderer(const std::vector<std::string>& command_line,
                      const base::GlobalDescriptors::Mapping& mapping);
   void EnsureProcessTerminated(pid_t process);
 
+  // Get the termination status (exit code) of the process and return true if
+  // the status indicates the process crashed. |child_exited| is set to true
+  // iff the child process has terminated. (|child_exited| may be NULL.)
+  bool DidProcessCrash(base::ProcessHandle handle, bool* child_exited);
+
   // These are the command codes used on the wire between the browser and the
   // zygote.
   enum {
-    kCmdFork = 0,  // Fork off a new renderer.
-    kCmdReap = 1,  // Reap a renderer child.
+    kCmdFork = 0,             // Fork off a new renderer.
+    kCmdReap = 1,             // Reap a renderer child.
+    kCmdDidProcessCrash = 2,  // Check if child process crashed.
   };
 
  private:
   friend struct DefaultSingletonTraits<ZygoteHost>;
   ZygoteHost();
   void LaunchZygoteProcess();
 
   int control_fd_;  // the socket to the zygote
 };
 
 #endif  // CHROME_BROWSER_ZYGOTE_HOST_LINUX_H_