MacViews: Adjust linux_ui guards in process_singleton_posix to match views.gyp

chrome/browser/process_singleton_posix.cc

Index: chrome/browser/process_singleton_posix.cc
diff --git a/chrome/browser/process_singleton_posix.cc b/chrome/browser/process_singleton_posix.cc
index ad678cae7aeff5a2a4523fb56b2aa6f4ccf858ea..efaab3f75ca610356955398badc09f0f52f99b96 100644
--- a/chrome/browser/process_singleton_posix.cc
+++ b/chrome/browser/process_singleton_posix.cc
@@ -85,7 +85,7 @@
 #include "chrome/browser/ui/process_singleton_dialog_linux.h"
 #endif
 
-#if defined(TOOLKIT_VIEWS) && !defined(OS_CHROMEOS)
+#if defined(TOOLKIT_VIEWS) && defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include "ui/views/linux_ui/linux_ui.h"
 #endif
 
@@ -860,7 +860,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
     // The other process is shutting down, it's safe to start a new process.
     return PROCESS_NONE;
   } else if (strncmp(buf, kACKToken, arraysize(kACKToken) - 1) == 0) {
-#if defined(TOOLKIT_VIEWS) && !defined(OS_CHROMEOS)
+#if defined(TOOLKIT_VIEWS) && defined(OS_LINUX) && !defined(OS_CHROMEOS)
     // Likely NULL in unit tests.
     views::LinuxUI* linux_ui = views::LinuxUI::instance();
     if (linux_ui)