Adds support for sending a query via deep link.

To accomplish this, this CL:
- Adds some utility methods to deep_link_utils for parsing params.
- Moves parameter keys to a unified place within deep_link_utils.
- Uses API to unescape parameters.
- Adds support for query via deep link.

Bug: b:111654253
Change-Id: Ic09ded6c76393fdc56006594ff01e64e8753ed0f
Reviewed-on: https://chromium-review.googlesource.com/1145829
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577776}
6 files changed