Fix testRepostFormAfterReload for slim-nav.

crrev.com/c/1632591 changed test behavior to wait until reload is
finished for slim nav, which broke the test.

This CL restores the original behavior, so the test does not wait until
reload is finished.

Added -[ChromeEarlGreyImpl reloadAndWaitForCompletion:] to compliment
existing -[ChromeEarlGreyImpl loadURL:waitForCompletion:]

Bug: 968296
Change-Id: I86d1d982424ee4f56c64ac4cae522f1070d116ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636570
Commit-Queue: Eugene But <[email protected]>
Reviewed-by: Justin Cohen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#664544}
3 files changed