MultiProcessTest: Update SpawnChild* to return a Process.

base/test/multiprocess_test.h

Index: base/test/multiprocess_test.h
diff --git a/base/test/multiprocess_test.h b/base/test/multiprocess_test.h
index b830f73ece7eca3c7398b0dd9352dbdc74267b92..e41950327a2d63fabd16df90d3c1d0904cda1c74 100644
--- a/base/test/multiprocess_test.h
+++ b/base/test/multiprocess_test.h
@@ -9,7 +9,7 @@
 
 #include "base/basictypes.h"
 #include "base/process/launch.h"
-#include "base/process/process_handle.h"
+#include "base/process/process.h"
 #include "build/build_config.h"
 #include "testing/platform_test.h"
 
@@ -58,7 +58,7 @@ class CommandLine;
 // |command_line| should be as provided by
 // |GetMultiProcessTestChildBaseCommandLine()| (below), possibly with arguments
 // added. Note: On Windows, you probably want to set |options.start_hidden|.
-ProcessHandle SpawnMultiProcessTestChild(
+Process SpawnMultiProcessTestChild(
     const std::string& procname,
     const CommandLine& command_line,
     const LaunchOptions& options);
@@ -105,14 +105,14 @@ class MultiProcessTest : public PlatformTest {
   //         // do client work here
   //    }
   //
-  // Returns the handle to the child, or NULL on failure
-  ProcessHandle SpawnChild(const std::string& procname);
+  // Returns the child process.
+  Process SpawnChild(const std::string& procname);
 
   // Run a child process using the given launch options.
   //
   // Note: On Windows, you probably want to set |options.start_hidden|.
-  ProcessHandle SpawnChildWithOptions(const std::string& procname,
-                                      const LaunchOptions& options);
+  Process SpawnChildWithOptions(const std::string& procname,
+                                const LaunchOptions& options);
 
   // Set up the command line used to spawn the child process.
   // Override this to add things to the command line (calling this first in the