[ObjC ARC] Converts ios/chrome/browser/payments:payments to ARC.

Automatically generated ARCMigrate commit
Notable issues:
- Removed multiple delegate getter/setter/ivar combos with synthesize
- Fixed memory management in several blocks, for example:
 __weak ShippingOptionSelectionCoordinator* weakSelf = self;
  dispatch_after(
      dispatch_time(DISPATCH_TIME_NOW,
                    static_cast<int64_t>(0.2 * NSEC_PER_SEC)),
      dispatch_get_main_queue(), ^{
        ShippingOptionSelectionCoordinator* strongSelf = weakSelf;
        // Early return if the coordinator has been deallocated.
        if (!strongSelf)
          return;
        [_viewController setIsLoading:YES];
}

last line retains self through dereferenced ivar. Also further in the same block:

        [_delegate shippingOptionSelectionCoordinator:self  didSelectShippingOption:shippingOption];

direct reference to |self|

* In PaymentRequestViewController the following ivars are now strong:
  PriceItem* _paymentSummaryItem;
  ShippingAddressItem* _selectedShippingAddressItem;
  CollectionViewTextItem* _selectedShippingOptionItem;
  PaymentMethodItem* _selectedPaymentMethodItem;

* For multiple view controllers with errorMessage property, it was changed from assign to copy as this seems to reflect de-facto usage.

BUG=624363
TEST=None

Review-Url: https://codereview.chromium.org/2710493006
Cr-Commit-Position: refs/heads/master@{#452891}
19 files changed