Review: https://chromium-review.googlesource.com/c/618571

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/716ce9bb9be21a000bc6c9afb14e477499a2f4c5

commit 716ce9bb9be21a000bc6c9afb14e477499a2f4c5
Author: Cezary Kulakowski <ckulakowski@opera.com>
Date: Thu Aug 17 18:35:12 2017

Add missing dependency to //base for target device_monitors

Because of lack of this dependency Build sometimes fails because of
missing file base/debug/debugging_flags.h:

[2017-08-17 10:18:12] [526/33287] CXX
obj/media/device_monitors/device_monitors/system_message_window_win.obj
[2017-08-17 10:18:12] >>BUILDBOT>>errors>>compile>>
[2017-08-17 10:18:12] FAILED:
obj/media/device_monitors/device_monitors/system_message_window_win.obj
[2017-08-17 10:18:12] ninja -t msvc -e environment.x64 --
c:\buildbot\clcache\bin/gomacc.exe "c:\program files (x86)\microsoft
visual studio 14.0\vc\bin\amd64/cl.exe" /nologo /showIncludes
@obj/media/device_monitors/device_monitors/system_message_window_win.obj.rsp
/c ../../media/device_monitors/system_message_window_win.cc
/Foobj/media/device_monitors/device_monitors/system_message_window_win.obj
/Fd"obj/media/device_monitors/device_monitors_cc.pdb"
[2017-08-17 10:18:12] CLCache Error: Failed to process compiler output
[2017-08-17 10:18:12] >>BUILDBOT>>errors>>compile>>
[2017-08-17 10:18:12] ../..\base/debug/stack_trace.h(14): fatal error
C1083: Cannot open include file: 'base/debug/debugging_flags.h':
No such file or directory

Bug:  756401 
Change-Id: I5468361db2558e082828eaba81458039167e6ab1
Reviewed-on: https://chromium-review.googlesource.com/618571
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495240}
[modify] https://crrev.com/716ce9bb9be21a000bc6c9afb14e477499a2f4c5/media/device_monitors/BUILD.gn