GitLab

* Replaces the previous "Select shipping address" or "Select shipping option"
  prompts with gigantic [SELECT] and [ADD] buttons on the right of each
  incomplete section.

* Caches a copy of the SectionInformation in the relevant PaymentRequestSection
  instances so that we can determine if we need to prompt the user to SELECT
  or ADD new PaymentOptions.

* Buttons are enabled from top to bottom, with only one button enabled at a
  time.  This encourages users to move downward while filling out the form.
  When a button is visible for a section, the only way to interact with the
  section is via the button (no more clicking on incomplete sections to expand
  them).

* The shipping summary section, which combines both the shipping address and
  shipping option fields, can now display a button that shows either the
  button for the incomplete shipping address section or the incomplete shipping
  option section (prioritized in taht order).

* Get rid of and generalizes a bunch of unneeded strings.

* Because the logic is so complicated now, we consolidate most layout updates
  and view visibility checks to updateControlLayout().

* Updates the PaymentRequestDynamicShippingSingleAddressTest to account for the
  lack of summary text for incomplete sections.

* Edits the "select shipping address" string to add "and requirements" to the end.

Videos:
https://drive.google.com/open?id=0B7c8ZkXVwskDZDZWUkhDXzdvLUE
https://drive.google.com/open?id=0B7c8ZkXVwskDRm53UUhHUHZmeW8

BUG=603635

Review-Url: https://codereview.chromium.org/2170693002
Cr-Commit-Position: refs/heads/master@{#407289}