Add a presubmit check that warns about declaring Singleton<T> in header files

Add a presubmit check that warns about declaring Singleton<T> in header files
(except for base/memory/singleton.h)
This check is copied from presubmit_canned_checks.py in depot_tools/ with an
added exception for base/memory/singleton.h.
The corresponding code will be removed from presubmit_canned_checks.py afterwards.

BUG=349861
R=phajdan.jr@chromium.org,

Committed: https://crrev.com/9b73d0393037452d13358f4e2766cb62adbdede8
Cr-Commit-Position: refs/heads/master@{#316546}

[Alexander Potapenko, 2015-02-16 13:20:52]

glider@chromium.org changed reviewers:
+ phajdan.jr@chromium.org
- jochen@chromium.org

[Alexander Potapenko, 2015-02-16 13:22:32]

Paweł, can you please take a look?
As noticed by M-A in https://codereview.chromium.org/924863002, there's no point
in having this Chromium-specific check in depot_tools.

[Paweł Hajdan Jr., 2015-02-16 15:18:52]

LGTM

[Alexander Potapenko, 2015-02-16 15:39:20]

On 2015/02/16 15:18:52, Paweł Hajdan Jr. wrote:
> LGTM
Just noticed there are tests for presubmit checks. Do I need one?

[Paweł Hajdan Jr., 2015-02-16 17:04:54]

On 2015/02/16 15:39:20, Alexander Potapenko wrote:
> Just noticed there are tests for presubmit checks. Do I need one?

Not if there wasn't one already.

[Alexander Potapenko, 2015-02-16 18:12:03]

New patchsets have been uploaded after l-g-t-m from phajdan.jr@chromium.org

[Alexander Potapenko, 2015-02-16 18:13:14]

On 2015/02/16 17:04:54, Paweł Hajdan Jr. wrote:
> On 2015/02/16 15:39:20, Alexander Potapenko wrote:
> > Just noticed there are tests for presubmit checks. Do I need one?
> 
> Not if there wasn't one already.

There was, so I added a similar one (plus a case for singleton.h)

[Paweł Hajdan Jr., 2015-02-16 19:08:32]

LGTM

[Alexander Potapenko, 2015-02-17 09:01:38]

The CQ bit was checked by glider@chromium.org

[commit-bot: I haz the power, 2015-02-17 09:02:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/929043002/20001

[commit-bot: I haz the power, 2015-02-17 09:26:28]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-17 09:27:14]

Patchset 2 (id:??) landed as
https://crrev.com/9b73d0393037452d13358f4e2766cb62adbdede8
Cr-Commit-Position: refs/heads/master@{#316546}

[Alexander Potapenko, 2015-02-17 11:17:21]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/934723003/ by glider@chromium.org.

The reason for reverting is: Reverting because of presubmit crashes:

Traceback (most recent call last):
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 2983, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 2969, in main
    return dispatcher.execute(OptionParser(), argv)
  File "/usr/local/google/ssd/depot_tools/subcommand.py", line 245, in execute
    return command(parser, args[1:])
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 1614, in CMDpresubmit
    change=cl.GetChange(base_branch, None))
  File "/usr/local/google/ssd/depot_tools/git_cl.py", line 936, in RunHook
    rietveld_obj=self.RpcServer())
  File "/usr/local/google/ssd/depot_tools/presubmit_support.py", line 1396, in
DoPresubmitChecks
    results += executer.ExecPresubmitScript(presubmit_script, filename)
  File "/usr/local/google/ssd/depot_tools/presubmit_support.py", line 1313, in
ExecPresubmitScript
    result = eval(function_name + '(*__args)', context)
  File "<string>", line 1, in <module>
  File "<string>", line 1727, in CheckChangeOnCommit
  File "<string>", line 1455, in _CommonChecks
  File "<string>", line 1322, in _CheckSingletonInHeaders
  File "/usr/local/google/ssd/depot_tools/presubmit_support.py", line 472, in
ReadFile
    raise IOError('Access outside the repository root is denied.')
IOError: Access outside the repository root is denied.
.