From https://uberchromegw.corp.google.com/i/internal.bling.main/builders/ipad9-device-x64/builds/10023, the following tests failed:

ReadingListTestCase.testSavingToReadingList
ReadingListTestCase.testMarkMixedEntriesRead
ReadingListTestCase.testVisibleButtonsOnlyUnreadEntrySelected
ReadingListTestCase.testDeleteEntries
ReadingListTestCase.testMarkMixedEntriesUnread
ReadingListTestCase.testVisibleButtonsEditingModeEmptySelection
ReadingListTestCase.testVisibleButtonsOnlyReadEntrySelected
ReadingListTestCase.testDeleteAllReadEntries
ReadingListTestCase.testMarkEntriesRead
ReadingListTestCase.testDeleteMultipleItems
ReadingListTestCase.testMarkEntriesUnread
ReadingListTestCase.testVisibleButtonsMixedEntriesSelected
ReadingListTestCase.testAccessibility
ReadingListTestCase.testMarkAllRead
ReadingListTestCase.testMarkAllUnread

Failure for the first test, ReadingListTestCase.testMarkMixedEntriesRead, assuming it may cause the other tests failures, is:

ReadingListTestCase.testSavingToReadingList: 
[0321/023555.697050:WARNING:most_visited_sites.cc(419)] Download of popular sites failed
../../ios/chrome/test/earl_grey/chrome_earl_grey_ui.mm:78: error: -[ReadingListTestCase testSavingToReadingList] : Exception: ConstraintFailedException

Exception Name: ConstraintFailedException
Exception Reason: Cannot perform action due to a constraint failure
Exception with Action: {
    "Action Name" = Tap;
    "Constraint Details" = "(!isSystemAlertViewShown && ((respondsToSelector(isAccessibilityElement) && isAccessibilityElement) || kindOfClass('UIView')) && (enabled && !((kindOfClass('UIView') || respondsToSelector(accessibilityContainer)) && ancestorThatMatches(!enabled))) && interactable)";
    "Element Description" = "<UIButton:0x159032d60; AX=Y; AX.id='kToolbarShareButtonIdentifier'; AX.label='Share\U2026'; AX.frame={{680, 63}, {46, 48}}; AX.activationPoint={703, 87}; AX.traits='UIAccessibilityTraitButton'; AX.focused='N'; frame={{680, 4}, {46, 48}}; alpha=1>";
    "Failed Constraint" = "!isSystemAlertViewShown";
    "Recovery Suggestion" = "Adjust element properties so that it matches the failed constraints.";
}

Exception Details: [
  {
    "Description" : "Cannot perform action due to a constraint failure.",
    "Domain" : "com.google.earlgrey.ElementInteractionErrorDomain",
    "Code" : "1",
    "File Name" : "GREYBaseAction.m",
    "Function Name" : "-[GREYBaseAction satisfiesConstraintsForElement:error:]",
    "Line" : "66",
    "TestCase Class" : "ReadingListTestCase",
    "TestCase Method" : "testSavingToReadingList"
  }
]

Bundle ID: com.google.gtest.ios-chrome-reading-list-egtests

Stack Trace: (
	0   EarlGrey                            0x0000000103bc1b10 -[GREYDefaultFailureHandler handleException:details:] + 1008
	1   EarlGrey                            0x0000000103bb9658 -[GREYElementInteraction grey_handleFailureOfAction:actionError:userProvidedOutError:] + 3372
	2   EarlGrey                            0x0000000103bb74d0 __46-[GREYElementInteraction performAction:error:]_block_invoke + 1184
	3   EarlGrey                            0x0000000103bd1db4 __59-[GREYUIThreadExecutor executeSyncWithTimeout:block:error:]_block_invoke + 40
	4   EarlGrey                            0x0000000103bcf794 __77-[GREYRunLoopSpinner grey_drainRunLoopInActiveModeAndCheckCondition:forTime:]_block_invoke + 280
	5   EarlGrey                            0x0000000103bd006c __89-[GREYRunLoopSpinner grey_setupObserverInMode:withBeforeSourcesBlock:beforeWaitingBlock:]_block_invoke + 324
	6   CoreFoundation                      0x0000000182018728 <redacted> + 32
	7   CoreFoundation                      0x00000001820164cc <redacted> + 372
	8   CoreFoundation                      0x0000000182016814 <redacted> + 696
	9   CoreFoundation                      0x0000000181f40c50 CFRunLoopRunSpecific + 384
	10  EarlGrey                            0x0000000103bcf4a8 -[GREYRunLoopSpinner grey_drainRunLoopInActiveModeAndCheckCondition:forTime:] + 400
	11  EarlGrey                            0x0000000103bcf094 -[GREYRunLoopSpinner spinWithStopConditionBlock:] + 596
	12  EarlGrey                            0x0000000103bd1a10 -[GREYUIThreadExecutor executeSyncWithTimeout:block:error:] + 788
	13  EarlGrey                            0x0000000103bb6b20 -[GREYElementInteraction performAction:error:] + 1208
	14  ios_chrome_reading_list_egtests     0x00000001000abcd8 +[ChromeEarlGreyUI openShareMenu] + 232
	15  ios_chrome_reading_list_egtests     0x00000001006fd258 -[ReadingListTestCase testSavingToReadingList] + 1244
	16  CoreFoundation                      0x0000000182068a60 <redacted> + 144
	17  CoreFoundation                      0x0000000181f60488 <redacted> + 284
	18  EarlGrey                            0x0000000103bb13b0 -[GREYTestCaseInvocation invoke] + 208
	19  XCTest                              0x0000000103a420a8 __24-[XCTestCase invokeTest]_block_invoke_2 + 388
	20  XCTest                              0x0000000103a76c98 -[XCTestContext performInScope:] + 208
	21  XCTest                              0x0000000103a41f0c -[XCTestCase invokeTest] + 268
	22  EarlGrey                            0x0000000103ba7a8c -[XCTestCase(GREYAdditions) grey_invokeTest] + 860
	23  XCTest                              0x0000000103a425e0 -[XCTestCase performTest:] + 460
	24  XCTest                              0x0000000103a3fa5c -[XCTestSuite performTest:] + 428
	25  XCTest                              0x0000000103a3fa5c -[XCTestSuite performTest:] + 428
	26  XCTest                              0x0000000103a3fa5c -[XCTestSuite performTest:] + 428
	27  XCTest                              0x0000000103a2b740 __25-[XCTestDriver _runSuite]_block_invoke + 56
	28  XCTest                              0x0000000103a4c260 -[XCTestObservationCenter _observeTestExecutionForBlock:] + 528
	29  XCTest                              0x0000000103a2b5d8 -[XCTestDriver _runSuite] + 460
	30  XCTest                              0x0000000103a2c3b4 -[XCTestDriver _checkForTestManager] + 296
	31  XCTest                              0x0000000103a78164 _XCTestMain + 628
	32  CoreFoundation                      0x0000000182018f84 <redacted> + 20
	33  CoreFoundation                      0x00000001820188bc <redacted> + 308
	34  CoreFoundation                      0x0000000182016820 <redacted> + 708
	35  CoreFoundation                      0x0000000181f40c50 CFRunLoopRunSpecific + 384
	36  GraphicsServices                    0x0000000183828088 GSEventRunModal + 180
	37  UIKit                               0x0000000187222088 UIApplicationMain + 204
	38  ios_chrome_reading_list_egtests     0x00000001000a70f0 main + 576
	39  libdyld.dylib                       0x0000000181ade8b8 <redacted> + 4
)