Point to build requirements page when there is a dependency check failure.

Tools/Scripts/webkitpy/layout_tests/port/base.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 365 matching lines @@
 
         def error_handler(script_error):
             local_error.exit_code = script_error.exit_code
 
         output = self._executive.run_command(cmd, error_handler=error_handler)
         if local_error.exit_code:
             _log.error('System dependencies check failed.')
             _log.error('To override, invoke with --nocheck-sys-deps')
             _log.error('')
             _log.error(output)
+            if self.host.platform.is_linux():
+                _log.error('')
+                _log.error('For complete Linux build requirements, please see:')
+                _log.error('https://code.google.com/p/chromium/wiki/LayoutTestsLinux')

[Dirk Pranke, 2014/03/20 18:17:58]

First, this is probably the wrong URL to link to; we should use
https://code.google.com/p/chromium/wiki/LinuxBuildInstructions instead, and
remove the bits about installing packages from LayoutTestsLinux altogether.

Second, I was troubled by the idea that we'd put a platform-specific check in
base.py (which we do sometimes, but I try to avoid), and also by the fact that
we're putting comments about build requirements in check_sys_deps() rather than
check_build(). If you look at win.py (for example), you'll see the same messages
in check_build() (with the Windows link, of course).

I think the right thing to do is to move this message into a
port._log_build_requirements_link() message, and refactor all of the port code
so that each port will log the right link if *either* check_sys_deps or
check_build() fails.

This shouldn't be very much work, and I think is the cleanest solution. Make
sense?

[Peter Beverloo, 2014/03/20 18:34:40]

install-build-deps.sh indeed includes all the packages listed on that page, so
the normal build instructions should be sufficient.
 
There is some precedence for this; sorry. I do agree that sharing a URL to build
instructions if either of the methods fails is a lot better. With the more
granular return messages we now have this shouldn't be hard to do, either.

             return test_run_results.SYS_DEPS_EXIT_STATUS
         return test_run_results.OK_EXIT_STATUS
 
     def check_image_diff(self, override_step=None, logging=True):
         """This routine is used to check whether image_diff binary exists."""
         image_diff_path = self._path_to_image_diff()
         if not self._filesystem.exists(image_diff_path):
             _log.error("image_diff was not found at %s" % image_diff_path)
             return False
         return True
@@ skipping 1350 matching lines @@
             if name.find('/') != -1:
                 _log.error("Virtual test suites names cannot contain /'s: %s" % name)
                 return
             self.name = 'virtual/' + name + '/' + base
         self.base = base
         self.args = args
         self.tests = tests or set()
 
     def __repr__(self):
         return "VirtualTestSuite('%s', '%s', %s)" % (self.name, self.base, self.args)