[Passwords, Mac] Don't always prompt to access passwords saved by other browsers

[Passwords, Mac] Don't always prompt to access passwords saved by other browsers

Specifically, disable the prompts when Chrome password management is disabled.
This gives users an escape hatch other than clicking "Always allow" or always
clicking "Deny" for each password prompt when they have passwords saved from
other browsers, especially if they don't want Chrome to access these.  This
previously regressed with https://chromiumcodereview.appspot.com/11361142/

BUG=178358
TEST=
  1. In *Safari*, navigate to a login page for which you can save a password.
  2. Log in, and instruct Safari to save the password.
  3. In *Chrome*, under Advanced Settings, disable password management.
  4. Navigate to the same login page.
  At step (4), there should be no prompt for authorization to access the
  password saved in Safari.

R=stuartmorgan@chromium.org

[Ilya Sherman, 2013-07-19 05:03:04]

Stuart, this CL is still a work in progress, but I wanted to get your thoughts
on the approach I'm pursing.  If you think the approach looks reasonable, I'll
try to add test coverage and resolve the couple of TODOs that still need to be
addressed.

[Ilya Sherman, 2013-07-27 00:02:30]

Note to self: It might be possible to greatly simplify this CL by leveraging
MacKeychainPasswordFormAdapter:: SetFindsOnlyOwnedItems().

[stuartmorgan, 2013-08-29 20:39:54]

Sorry for the delay, this pretty much LG, but a couple questions.

As for FindOnlyOwned, I'd rather you stick with the code here. If someone has
authorized an item created by another browser, we shouldn't exclude it in the
no-prompt case; that would be simpler code, but it would be an approximation of
the documented effect.

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
File chrome/browser/password_manager/password_form_manager.cc (left):

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
chrome/browser/password_manager/password_form_manager.cc:254: }
Why change this?

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
File chrome/browser/password_manager/password_manager.cc (right):

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
chrome/browser/password_manager/password_manager.cc:271:
PasswordStore::DISALLOW_PROMPT;
Optional: Looks like it would fit to pull this up to:
   foo ? bar
       : baz
which seems more readable; this looks like an argument list rather than a
ternary to me when skimming.

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
File chrome/browser/password_manager/password_store.h (right):

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
chrome/browser/password_manager/password_store.h:117: // passwords. This
variable currently is a no-op on platforms other than Mac.
Seems unlikely that anyone would think to come change this comment. How about
"... no-op except on platforms that can prompt for password access (such as
Mac).

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
File chrome/browser/password_manager/password_store_mac.cc (right):

https://codereview.chromium.org/19775014/diff/1/chrome/browser/password_manag...
chrome/browser/password_manager/password_store_mac.cc:569: // TODO(isherman):
Pass a real value.
Is this a long-term TODO, or something to fix now?

[Raghu Simha, 2013-08-30 01:23:21]

On 2013/07/27 00:02:30, Ilya Sherman wrote:
> Note to self: It might be possible to greatly simplify this CL by leveraging
> MacKeychainPasswordFormAdapter:: SetFindsOnlyOwnedItems().

On 2013/08/29 20:39:54, stuartmorgan wrote:
> As for FindOnlyOwned, I'd rather you stick with the code here. If someone has
> authorized an item created by another browser, we shouldn't exclude it in the
> no-prompt case; that would be simpler code, but it would be an approximation
of
> the documented effect.

I noticed a variant of this issue while I was experimenting with a way to speed
up password model association for sync in
https://codereview.chromium.org/23477015. When I tried loading passwords from
the keychain after calling
MacKeychainPasswordFormAdapter::SetFindsOnlyOwnedItems(true), only a subset of
chrome's synced passwords were returned, because some of them had been added to
the keychain by Google Chrome and some others by Chromium.