Support attribute lists for mojom imports.

Update the definition of the Import class in
//mojo/public/tools/bindings/pylib/mojom/parse/ast.py to have
an attribute list.

Update the grammar in
//mojo/public/tools/bindings/pylib/mojo/parse/parser.py so that
imports are now preceded by an attribute_section.

Update existing tests in parser_unittests.py and add
a unit test for Imports with attributes to
conditional_features_unittest.py

Bug: 676224
Change-Id: If347ef41f9149d3587db1f79abba84ccf552dbc2
Reviewed-on: https://chromium-review.googlesource.com/934004
Commit-Queue: Eve Martin-Jones <evem@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538937}

CrOS-Libchrome-Original-Commit: 55b8e2e73a7448a10a8b751c450eb636b2abb7d3
5 files changed
tree: 5781846d6c46ec11a7c172dd218b1e432791595a
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/