GitLab

Context:
PaymentRequestEvent.OpenWindow() promise should be resolved to be a
window client. With ExpandablePaymentHandler enabled, OpenWindow is
never resolved. This makes a payment app service worker fail to send a
message to the payment app js since it relies on the resolved
WindowClient.

Before Change:
With ExpandablePaymentHandler enabled, PaymentRequestEvent.OpenWindow()
is never resolved.

After Change:
With ExpandablePaymentHandler enabled, OpenWindow is resolved upon
initializing the WebContents of PaymentHandler.

Change:
Notify ServiceTabLaunch when Expandable PH UI has initialized
WebContents, so that ServiceTabLaunch can resolve the OpenWindow()
promise.

Bug: 1045955

Change-Id: I3fae5f90d144d27e97044f175478072743de05aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2037643Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Commit-Queue: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738572}