Remove unused ResourceLoaderOptions functionality.

Retire the enumerations ClientCrossOriginCredentialPolicy and
SecurityCheckPolicy, and their storage on the resource loader options
struct. Neither is made use of during resource loading.

The propagation of a SecurityCheckPolicy setting when issuing a load
request by the 'threadable' document loaders is as a result also no
longer done.

R=
BUG=

Review URL: https://codereview.chromium.org/167293003

git-svn-id: svn://svn.chromium.org/blink/trunk@167237 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove DisableCompositingQueryAsserts from RenderLayer::hitTest.

This assert doesn't hit in any layout tests. Conceptually, hit
testing shouldn't depend on compositor state, so that makes some sense.

BUG=343775

Review URL: https://codereview.chromium.org/167573005

git-svn-id: svn://svn.chromium.org/blink/trunk@167238 bbb929c8-8fbe-4397-9dbb-9b2b20218538