Create a stub chrome executable that crashes when run.

base/base_lib.scons

Index: base/base_lib.scons
diff --git a/base/base_lib.scons b/base/base_lib.scons
index afb82eae0a55d10d93bc3e03563a79a2c9d155c6..ac27c3c03d6a4e0a7d9174621c539feb357e9ebf 100644
--- a/base/base_lib.scons
+++ b/base/base_lib.scons
@@ -277,8 +277,9 @@ if env.Bit('posix'):
     'event_recorder.cc',
     'file_version_info.cc',
 
-    # We have an implementation of idle_timer, but it's unclear if we want it
-    # yet, so it's commented out for now.  Leave this 'unported'.
+    # We have an implementation of idle_timer that depends on XScreenSaver,
+    # but it's unclear if we want it yet, so it's commented out for now.
+    # Leave this 'unported'.
     'idle_timer.cc',
 
     'object_watcher.cc',
@@ -286,6 +287,11 @@ if env.Bit('posix'):
     'resource_util.cc',  # Uses HMODULE, but may be abstractable.
   )
 
+  input_files.Append(
+    # See above note about idle_timer.cc.
+    'idle_timer_none.cc',
+  )
+
 if not env.Bit('windows'):
   # Remove windows-specific files on non-Windows platforms.
   # TODO(sgk):