Move infobar constants and the code that uses them from components/ to chrome/.
Both the infobar and the infobar container were making use of various infobar
constants that were declared in components/ but (usually) defined in chrome/.
This was a symptom of having put code in the component that really probably
belonged in the embedder.
This CL hoists the relevant logic to a new cross-platform
InfoBarContainerDelegate class defined on the chrome side, which implements some
of the methods of InfoBarContainer::Delegate. Platforms then subclass this to
implement the remaining, platform-specific bits.
This means that the constants in question now live solely in chrome/, avoiding a
bunch of link-time nastiness when trying to build the components code
separately.
BUG=382924
TEST=none
TBR=finnur
Review URL: https://codereview.chromium.org/
793783003
Cr-Commit-Position: refs/heads/master@{#308046}