[PR] Fixes the flaky PaymentRequestShowEGTest.testBuyWithResolvingPromise

-As EG synchronization is disabled, manually waits until payment screen
 shows.
-Clears profiles before starting each test, so that each test starts with
 a clean state.

Bug:833562

Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I4e21537e91e57a7f38ff3715f4999ad73481eb56
Reviewed-on: https://chromium-review.googlesource.com/1059654Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559444}

ios/chrome/browser/ui/payments/payment_request_egtest_base.mm

@@ -67,6 +67,12 @@ const NSTimeInterval kPDMMaxDelaySeconds = 10.0;
   _personalDataManager =
       autofill::PersonalDataManagerFactory::GetForBrowserState(
           chrome_test_util::GetOriginalBrowserState());
+
+  // Before starting, clear existing profiles.
+  for (const auto* profile : _personalDataManager->GetProfiles()) {
+    [self personalDataManager]->RemoveByGUID(profile->guid());
+  }
+
   _personalDataManager->SetSyncingForTest(true);
 }
 

ios/chrome/browser/ui/payments/payment_request_show_egtest.mm

@@ -90,9 +90,17 @@ id<GREYMatcher> PriceCellMatcher(NSString* accessibilityLabel) {
 
   [ChromeEarlGrey tapWebViewElementWithID:@"buyWithResolvingPromise"];
 
-  // Confirm that the Payment Request UI is showing.
-  [[EarlGrey selectElementWithMatcher:chrome_test_util::PaymentRequestView()]
-      assertWithMatcher:grey_notNil()];
+  // Wait until the payment request view shows.
+  ConditionBlock condition = ^{
+    NSError* error = nil;
+    [[EarlGrey selectElementWithMatcher:chrome_test_util::PaymentRequestView()]
+        assertWithMatcher:grey_notNil()
+                    error:&error];
+    return error == nil;
+  };
+  GREYAssert(
+      testing::WaitUntilConditionOrTimeout(kShowPromiseTimeout, condition),
+      @"Payment request view failed to show.");
 
   // Verify that the Buy button is not enabled.
   [[EarlGrey selectElementWithMatcher:ButtonWithAccessibilityLabelId(
@@ -100,7 +108,7 @@ id<GREYMatcher> PriceCellMatcher(NSString* accessibilityLabel) {
       assertWithMatcher:grey_not(grey_enabled())];
 
   // Wait until the Buy button becomes enabled.
-  ConditionBlock condition = ^{
+  condition = ^{
     NSError* error = nil;
     [[EarlGrey selectElementWithMatcher:ButtonWithAccessibilityLabelId(
                                             IDS_PAYMENTS_PAY_BUTTON)]