In the reported failure, the error was 

D StrictMode: StrictMode policy violation; ~duration=534 ms: android.os.StrictMode$StrictModeDiskReadViolation: policy=2911 violation=2
D StrictMode: 	at android.os.StrictMode$AndroidBlockGuardPolicy.onReadFromDisk(StrictMode.java:1135)
...
D StrictMode: # via Binder call with stack:
D StrictMode: android.os.StrictMode$LogStackTrace
D StrictMode: 	at android.os.StrictMode.readAndHandleBinderCallViolations(StrictMode.java:1705)
D StrictMode: 	at android.os.Parcel.readExceptionCode(Parcel.java:1447)
D StrictMode: 	at android.os.Parcel.readException(Parcel.java:1416)
D StrictMode: 	at android.app.ActivityManagerProxy.checkPermission(ActivityManagerNative.java:3414)
D StrictMode: 	at android.app.ContextImpl.checkPermission(ContextImpl.java:1659)
D StrictMode: 	at android.app.ContextImpl.checkCallingOrSelfPermission(ContextImpl.java:1685)
D StrictMode: 	at android.view.accessibility.AccessibilityManager.getInstance(AccessibilityManager.java:168)
D StrictMode: 	at android.app.ContextImpl$2.getService(ContextImpl.java:318)
D StrictMode: 	at android.app.ContextImpl.getSystemService(ContextImpl.java:1632)
D StrictMode: 	at android.content.ContextWrapper.getSystemService(ContextWrapper.java:540)
D StrictMode: 	at org.chromium.ui.base.WindowAndroid.<init>(WindowAndroid.java:218)
D StrictMode: 	at org.chromium.ui.base.WindowAndroid.<init>(WindowAndroid.java:200)
D StrictMode: 	at org.chromium.ui.base.ActivityWindowAndroid.<init>(ActivityWindowAndroid.java:69)
D StrictMode: 	at org.chromium.ui.base.ActivityWindowAndroid.<init>(ActivityWindowAndroid.java:60)
D StrictMode: 	at org.chromium.chrome.browser.ChromeWindow.<init>(ChromeWindow.java:24)
D StrictMode: 	at org.chromium.chrome.browser.ChromeActivity.createWindowAndroid(ChromeActivity.java:308)
D StrictMode: 	at org.chromium.chrome.browser.init.AsyncInitializationActivity.onCreateInternal(AsyncInitializationActivity.java:298)
D StrictMode: 	at org.chromium.chrome.browser.init.AsyncInitializationActivity.onCreate(AsyncInitializationActivity.java:244)
D StrictMode: 	at android.app.Activity.performCreate(Activity.java:5231)
D StrictMode: 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
D StrictMode: 	at android.support.test.runner.MonitoringInstrumentation.callActivityOnCreate(MonitoringInstrumentation.java:532)
D StrictMode: 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
D StrictMode: 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
D StrictMode: 	at android.app.ActivityThread.access$800(ActivityThread.java:135)
D StrictMode: 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
D StrictMode: 	at android.os.Handler.dispatchMessage(Handler.java:102)
D StrictMode: 	at android.os.Looper.loop(Looper.java:136)
D StrictMode: 	at android.app.ActivityThread.main(ActivityThread.java:5001)
D StrictMode: 	at java.lang.reflect.Method.invokeNative(Native Method)
D StrictMode: 	at java.lang.reflect.Method.invoke(Method.java:515)
D StrictMode: 	at com.android.internal.os.ZygoteI

Not sure how a StrictMode violation can be raised there, as WindowAndroid's constructor allows them (see crashing line 218, change made in  issue 767624 )

Merging into issue 776350 that is also about a random StrictMode violation in unrelated code.