See the failure rate on Lollipop Phone Tester:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=chrome_public_test_apk&tests=org.chromium.chrome.browser.preferences.password.SavePasswordsPreferencesTest%23testExportMenuItemNoLock

Fails with:
C  872.981s Main  [FAIL] org.chromium.chrome.browser.preferences.password.SavePasswordsPreferencesTest#testExportMenuItemNoLock:
C  872.981s Main  android.support.test.espresso.NoMatchingViewException: No views in hierarchy found matching: with string from resource id: <2131427599>[password_export_set_lock_screen] value: Turn on screen lock in Settings to export your passwords from this device
C  872.981s Main  If the target view is not part of the view hierarchy, you may need to use Espresso.onData to load it from one of the following AdapterViews:android.widget.ListView{168a05e3 VFED.VC. .F...... 0,0-1080,1533 #102000a android:id/list}
C  872.982s Main  
....
C  872.984s Main  	at dalvik.system.VMStack.getThreadStackTrace(Native Method)
C  872.984s Main  	at java.lang.Thread.getStackTrace(Thread.java:580)
C  872.984s Main  	at android.support.test.espresso.base.DefaultFailureHandler.getUserFriendlyError(DefaultFailureHandler.java:82)
C  872.984s Main  	at android.support.test.espresso.base.DefaultFailureHandler.handle(DefaultFailureHandler.java:53)
C  872.984s Main  	at android.support.test.espresso.ViewInteraction.runSynchronouslyOnUiThread(ViewInteraction.java:184)
C  872.984s Main  	at android.support.test.espresso.ViewInteraction.check(ViewInteraction.java:158)
C  872.984s Main  	at org.chromium.chrome.browser.preferences.password.SavePasswordsPreferencesTest.testExportMenuItemNoLock(SavePasswordsPreferencesTest.java:405)
C  872.984s Main  	at java.lang.reflect.Method.invoke(Native Method)
C  872.984s Main  	at java.lang.reflect.Method.invoke(Method.java:372)
C  872.984s Main  	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
C  872.984s Main  	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
C  872.984s Main  	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:52)
C  872.984s Main  	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
C  872.984s Main  	at org.chromium.base.test.ScreenshotOnFailureStatement.evaluate(ScreenshotOnFailureStatement.java:37)
C  872.984s Main  	at org.chromium.chrome.browser.test.ChromeBrowserTestRule$1.evaluate(ChromeBrowserTestRule.java:40)
C  872.984s Main  	at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
C  872.984s Main  	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
C  872.984s Main  	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
C  872.984s Main  	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
C  872.984s Main  	at org.chromium.base.test.BaseJUnit4ClassRunner.runChild(BaseJUnit4ClassRunner.java:184)
C  872.984s Main  	at org.chromium.base.test.BaseJUnit4ClassRunner.runChild(BaseJUnit4ClassRunner.java:41)
C  872.984s Main  	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
C  872.984s Main  	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
C  872.984s Main  	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
C  872.984s Main  	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
C  872.984s Main  	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
C  872.984s Main  	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
C  872.984s Main  	at org.chromium.base.test.BaseJUnit4ClassRunner.run(BaseJUnit4ClassRunner.java:166)
C  872.984s Main  	at org.junit.runners.Suite.runChild(Suite.java:128)
C  872.984s Main  	at org.junit.runners.Suite.runChild(Suite.java:27)
C  872.984s Main  	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
C  872.984s Main  	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
C  872.984s Main  	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
C  872.984s Main  	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
C  872.985s Main  	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
C  872.985s Main  	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
C  872.985s Main  	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
C  872.985s Main  	at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
C  872.985s Main  	at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:59)
C  872.985s Main  	at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:262)
C  872.985s Main  	at org.chromium.base.test.BaseChromiumAndroidJUnitRunner.onStart(BaseChromiumAndroidJUnitRunner.java:99)
C  872.985s Main  	at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1853)


This test was added in https://chromium-review.googlesource.com/c/chromium/src/+/797453, so assigning to author.