[Mac] Remove base::LaunchSynchronize and rewrite content::MachBroker.

base/process_util.h

Index: base/process_util.h
diff --git a/base/process_util.h b/base/process_util.h
index 54d8533ce61231f838dc8fbae25b5156764acfc4..a06f689f91ea39d33ba703dc52f1d2607e2e6e45 100644
--- a/base/process_util.h
+++ b/base/process_util.h
@@ -232,13 +232,6 @@ BASE_EXPORT void CloseSuperfluousFds(const InjectiveMultimap& saved_map);
 typedef std::vector<std::pair<std::string, std::string> > EnvironmentVector;
 typedef std::vector<std::pair<int, int> > FileHandleMappingVector;
 
-#if defined(OS_MACOSX)
-// Used with LaunchOptions::synchronize and LaunchSynchronize, a
-// LaunchSynchronizationHandle is an opaque value that LaunchProcess will
-// create and set, and that LaunchSynchronize will consume and destroy.
-typedef int* LaunchSynchronizationHandle;
-#endif  // defined(OS_MACOSX)
-
 // Options for launching a subprocess that are passed to LaunchProcess().
 // The default constructor constructs the object with default options.
 struct LaunchOptions {
@@ -266,9 +259,6 @@ struct LaunchOptions {
 #if defined(OS_CHROMEOS)
       , ctrl_terminal_fd(-1)
 #endif  // OS_CHROMEOS
-#if defined(OS_MACOSX)
-      , synchronize(NULL)
-#endif  // defined(OS_MACOSX)
 #endif  // !defined(OS_WIN)
   {}
 
@@ -350,27 +340,6 @@ struct LaunchOptions {
   int ctrl_terminal_fd;
 #endif  // defined(OS_CHROMEOS)
 
-#if defined(OS_MACOSX)
-  // When non-NULL, a new LaunchSynchronizationHandle will be created and
-  // stored in *synchronize whenever LaunchProcess returns true in the parent
-  // process. The child process will have been created (with fork) but will
-  // be waiting (before exec) for the parent to call LaunchSynchronize with
-  // this handle. Only when LaunchSynchronize is called will the child be
-  // permitted to continue execution and call exec. LaunchSynchronize
-  // destroys the handle created by LaunchProcess.
-  //
-  // When synchronize is non-NULL, the parent must call LaunchSynchronize
-  // whenever LaunchProcess returns true. No exceptions.
-  //
-  // Synchronization is useful when the parent process needs to guarantee that
-  // it can take some action (such as recording the newly-forked child's
-  // process ID) before the child does something (such as using its process ID
-  // to communicate with its parent).
-  //
-  // |synchronize| and |wait| must not both be set simultaneously.
-  LaunchSynchronizationHandle* synchronize;
-#endif  // defined(OS_MACOSX)
-
 #endif  // !defined(OS_WIN)
 };
 
@@ -442,15 +411,6 @@ BASE_EXPORT bool LaunchProcess(const std::vector<std::string>& argv,
 // The returned array is allocated using new[] and must be freed by the caller.
 BASE_EXPORT char** AlterEnvironment(const EnvironmentVector& changes,
                                     const char* const* const env);
-
-#if defined(OS_MACOSX)
-
-// After a successful call to LaunchProcess with LaunchOptions::synchronize
-// set, the parent process must call LaunchSynchronize to allow the child
-// process to proceed, and to destroy the LaunchSynchronizationHandle.
-BASE_EXPORT void LaunchSynchronize(LaunchSynchronizationHandle handle);
-
-#endif  // defined(OS_MACOSX)
 #endif  // defined(OS_POSIX)
 
 #if defined(OS_WIN)