This issue seems to be a Robolectric framework bug.
https://github.com/robolectric/robolectric/issues/2024

Setting sdk=18 fixes this issue. When Robolectric is updated, this test should be tried with the updated sdk version.

The test failure with sdk=21 is pasted below.

[ RUN      ] org.chromium.ui.picker.DateDialogNormalizerTest.testNormalize
java.lang.IllegalArgumentException: Bad pattern character 'h' in h:mm a
	at libcore.icu.ICU.getDateFormatOrder(ICU.java:314)
	at android.widget.DatePicker$DatePickerSpinnerDelegate.reorderSpinners(DatePicker.java:947)
	at android.widget.DatePicker$DatePickerSpinnerDelegate.__constructor__(DatePicker.java:702)
	at android.widget.DatePicker$DatePickerSpinnerDelegate.<init>(DatePicker.java)
	at android.widget.DatePicker.createSpinnerUIDelegate(DatePicker.java:148)
	at android.widget.DatePicker.__constructor__(DatePicker.java:137)
	at android.widget.DatePicker.<init>(DatePicker.java)
	at org.chromium.ui.picker.DateDialogNormalizerTest.run(DateDialogNormalizerTest.java:80)
	at org.chromium.ui.picker.DateDialogNormalizerTest.testNormalize(DateDialogNormalizerTest.java:98)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:238)
	at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:175)
	at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:53)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:139)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.chromium.testing.local.GtestComputer$GtestSuiteRunner.run(GtestComputer.java:46)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:24)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:136)
	at org.chromium.testing.local.JunitTestMain.main(JunitTestMain.java:105)
[   FAILED ] org.chromium.ui.picker.DateDialogNormalizerTest.testNormalize (9123 ms)