GN: Attach the scope provider to imported files.

This enables imports to use the built-in programatic variables like root_build_dir.

R=scottmg@chromium.org, scottmg

Review URL: https://codereview.chromium.org/126033006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243444 0039d316-1c4b-4281-b951-d872f2087c98
Revert 242936 "When stopping QTKit video capture, call stopRunni..."

This CL removed a deadlock on camera removal, but created a new one
on shutdown while a camera is running.

> When stopping QTKit video capture, call stopRunning before removeInput:.
> 
> Empirically, this prevents a browser hang when the active camera is
> unplugged.  The unplug event triggers both stopping the capturer and
> enumerating the available input devices at the same time.  It seems
> that calling removeInput: on a running capturer after an error
> produces a deadlock, but stopping the capturer first resolves the
> problem.
> 
> BUG=285053
> 
> Review URL: https://codereview.chromium.org/120963003

TBR=bemasc@chromium.org

Review URL: https://codereview.chromium.org/126883005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243445 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243444
SVN changes up to revision 243445
GN Command line -D parsing, goma on Windows

This makes gyp_chromium pass defines defined via -D on the command line to GN.

Fixes double-escaping of strings from supplemental.gypi files.

Pass use_goma to the GN build.

Handle "use_goma" and "use_goma=1" (same for other boolean values). Previously values with no equals sign were getting converted to 'true', which doesn't match '1' which we look for.

Output goma wrappers in the GYP header for Windows toolchains.

R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/123463005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243446 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243446