junit tests don't run anymore both locally and on some bots on the CQ: 

Sample build: https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/182679

java.lang.IllegalArgumentException: File does not exist: /b/c/b/android/src/out/Release/lib.java/third_party/robolectric/shadows-core-3.0-21.jar
	at org.robolectric.internal.dependency.LocalDependencyResolver.validateFile(LocalDependencyResolver.java:55)
	at org.robolectric.internal.dependency.LocalDependencyResolver.getLocalArtifactUrl(LocalDependencyResolver.java:32)
	at org.robolectric.internal.dependency.LocalDependencyResolver.getLocalArtifactUrls(LocalDependencyResolver.java:40)
	at org.robolectric.internal.InstrumentingClassLoaderFactory.getSdkEnvironment(InstrumentingClassLoaderFactory.java:39)
	at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:174)
	at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:53)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:139)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.chromium.testing.local.GtestComputer$GtestSuiteRunner.run(GtestComputer.java:46)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:27)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
	at org.chromium.testing.local.JunitTestMain.main(JunitTestMain.java:105)
[   FAILED ] org.chromium.chrome.browser.ChromeBackupAgentTest.testOnBackup_dataChanged (1 ms)


I fixed it locally by running:

% cp $CHROMIUM_SRC/out/Debug/lib.java/third_party/robolectric/shadows-core-3.0-21_java.jar $CHROMIUM_SRC/out/Debug/lib.java/third_party/robolectric/shadows-core-3.0-21.jar