Add File::Open / Create functions to take an rtc::Pathname

When implementing ISOLATED_OUTDIR feature in WebRTC, I found two issues,
1. pathutils and flags are not accessible in testsupport. But both of them are
useful for the feature. Pathname can help to combine path with filename, while
a flag is needed to handle command line parameter.
2. rtc::File cannot accept an rtc::Pathname, which is a little bit inconvenient.

After investigating bug webrtc:3806, flags, pathutils and urlencode are
removed from rtc_base_approved because of the including of common.h. So I
replaced common.h with checks.h, and ASSERT with RTC_DCHECK. flags,
pathutils and urlencode pairs now can be placed into rtc_base_approved to
unblock file.h to include pathutils.h.

Please kindly let me know if you have other concerns about this change.

BUG=webrtc:3806, webrtc:6732

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_rel_ng;master.tryserver.chromium.mac:mac_chromium_rel_ng;master.tryserver.chromium.win:win_chromium_rel_ng;master.tryserver.chromium.android:linux_android_rel_ng

Review-Url: https://codereview.webrtc.org/2533213005
Cr-Commit-Position: refs/heads/master@{#15451}
9 files changed
tree: 48437e3f843910c217d9520ead1ed6cb908cae7b
  1. build_overrides/
  2. chromium/
  3. data/
  4. infra/
  5. resources/
  6. third_party/
  7. tools/
  8. webrtc/
  9. .clang-format
  10. .git-blame-ignore-revs
  11. .gitignore
  12. .gn
  13. AUTHORS
  14. BUILD.gn
  15. check_root_dir.py
  16. codereview.settings
  17. DEPS
  18. LICENSE
  19. license_template.txt
  20. LICENSE_THIRD_PARTY
  21. OWNERS
  22. PATENTS
  23. PRESUBMIT.py
  24. pylintrc
  25. README.md
  26. setup_links.py
  27. sync_chromium.py
  28. WATCHLISTS
README.md

WebRTC is a free, open software project that provides browsers and mobile applications with Real-Time Communications (RTC) capabilities via simple APIs. The WebRTC components have been optimized to best serve this purpose.

Our mission: To enable rich, high-quality RTC applications to be developed for the browser, mobile platforms, and IoT devices, and allow them all to communicate via a common set of protocols.

The WebRTC initiative is a project supported by Google, Mozilla and Opera, amongst others. This page is maintained by the Google Chrome team.

Development

See http://www.webrtc.org/native-code/development for instructions on how to get started developing with the native code.

More info