Template invocation fixes in GN

Template invocation fixes in GN

This adds an error check when invoking templates which caused really confusing messages if the template invocation encountered an error (because we'd continue running).

Hooks up the provider for programatically defined variables in template invocations so those can be used.

Sets the current directory in a template invocation to be that of the invoking file.

No longer define the target-related programatic variables in an import. Using these in an import will give the directory relative to the import, which is probabyl not what you want.

Fix the Windows build by adding a missing library. Add a warning not to add more to the main list (this added .lib is pretty obscure).

BUG=
R=cjhopman@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=262524

[cjhopman, 2014-04-08 21:20:40]

lgtm

https://codereview.chromium.org/226223006/diff/20001/base/BUILD.gn
File base/BUILD.gn (right):

https://codereview.chromium.org/226223006/diff/20001/base/BUILD.gn#newcode760
base/BUILD.gn:760: libs = [ "netapi32.lib" ]
Having the windows build fix in this change is a bit odd.

[brettw, 2014-04-08 22:33:53]

On 2014/04/08 21:20:40, cjhopman wrote:
> lgtm
> 
> https://codereview.chromium.org/226223006/diff/20001/base/BUILD.gn
> File base/BUILD.gn (right):
> 
> https://codereview.chromium.org/226223006/diff/20001/base/BUILD.gn#newcode760
> base/BUILD.gn:760: libs = [ "netapi32.lib" ]
> Having the windows build fix in this change is a bit odd.

I couldn't compile it without this (I did it on Windows).

[brettw, 2014-04-08 22:35:22]

Committed patchset #2 manually as r262524 (presubmit successful).