Revert 290058 "Omnibox: Prevent Asynchronous Suggestions from Ch..."

Revert 290058 "Omnibox: Prevent Asynchronous Suggestions from Ch..."

This change closed the build tree for Linux and ChromiumOS bots due to
failing interactive_ui_tests:

http://build.chromium.org/p/chromium.linux/buildstatus?builder=Linux%20Tests&number=12979

> Omnibox: Prevent Asynchronous Suggestions from Changing Default Match
> 
> Calls to the suggest server may normally result in a new inline
> autocompletion.  This can be disruptive because it means pressing enter
> may bring the user to different places depending on how long he/she
> waits after typing the last key.
> 
> This change prevents new suggestions from becoming the default match.
> In other words, the default match is only allowed to change on a
> keystroke, not due to a reply coming back from the server.
> 
> The consequence of this change is that if previously we'd show an
> inline suggestion on a server reply, now we only show it one keystroke
> later.  I think this trade-off (one keystroke versus inconsistent
> omnibox behavior) is a good one to make.
> 
> We still end up with default matches (inline autocompletions within
> the omnibox) from the suggest server after this change.  Here's an
> example of why:
> 
> User types "facebo"
> We send a suggest server request.
> Server asynchronously returns "facebook" as a top suggestion,
>   beating the server-provided verbatim score for "facebo".
> We decide not to show it within the omnibox.  It's instead shown
>   somewhere in the dropdown.
> User types "o".
> We send a suggest server request.
> We reuse our cached suggestions and suggestion scores.  <<< THE KEY
> We show "facebook" as an inline suggestion because it beats
>   the default verbatim score that gets assigned to "faceboo".
>   (This is the score that we assign by default without having
>   yet received the most recent suggest server response.)
> We receive the response, which includes "facebook" as a top
>   suggestion, beating the server-provided verbatim score
>   for "faceboo".
> We show "facebook" as an inline suggestion.  i.e., we decide
>   not to demote it because it was already being shown inline
> 
> TESTED:
> unit tests plus interactive tests (facebook.com/l, google.com/a)
> 
> BUG=398135
> R=msw@chromium.org
> 
> Review URL: https://codereview.chromium.org/471673002

TBR=mpearson@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=290070

[miu, 2014-08-16 00:55:55]

Committed patchset #1 manually as r290070 (tree was closed).

[miu, 2014-08-16 00:56:50]

Please use the CQ!