Prelaunch processes from post install dialog in Windows

This is a follow up to my previous commit [1], which started executing
the following command

 mozc_broker --mode=prelaunch_processes

to pre-launch 'mozc_server' and 'mozc_renderer' whenever the user logs
in on Windows because these processes cannot be launched from sandboxed
processes such as 'SearchHost.exe'.

With this commit, effectively the same workaround will be performed
after installing Mozc and while executing post install dialog.

Closes #845.

 [1]: 0488082

PiperOrigin-RevId: 582383447

src/gui/post_install_dialog/BUILD.bazel

@@ -93,7 +93,11 @@ mozc_cc_qt_library(
         "//gui/base:singleton_window_helper",
         "//usage_stats",
     ] + mozc_select(
-        windows = ["//base/win32:scoped_com"],
+        windows = [
+            "//base:const",
+            "//base:process",
+            "//base/win32:scoped_com",
+        ],
     ),
 )
 

src/gui/post_install_dialog/post_install_dialog_libmain.cc

@@ -42,6 +42,8 @@
 #include "gui/post_install_dialog/post_install_dialog.h"
 
 #ifdef _WIN32
+#include "base/const.h"
+#include "base/process.h"
 #include "base/win32/scoped_com.h"
 #endif  // _WIN32
 
@@ -50,6 +52,11 @@ int RunPostInstallDialog(int argc, char *argv[]) {
 
   mozc::SystemUtil::DisableIME();
 
+#ifdef _WIN32
+  mozc::Process::SpawnMozcProcess(mozc::kMozcBroker,
+                                  "--mode=prelaunch_processes");
+#endif  // _WIN32
+
   std::string name = "post_install_dialog.";
   name += mozc::SystemUtil::GetDesktopNameAsString();