[Android] Check for Java object types covariance in Java Bridge

ART does check covariance of types passed via JNI anyway, causing the VM to
crash if they doesn't. We'd better check this in Java Bridge and throw a
JavaScript exception, as LiveConnect spec suggests.

BUG=392489

Review URL: https://codereview.chromium.org/393733002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@283457 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/findbugs_filter/findbugs_known_bugs.txt

@@ -1,4 +1,3 @@
-H C EC: Using pointer equality to compare a JavaBridgeCoercionTest$CustomType with a JavaBridgeCoercionTest$CustomType2 in org.chromium.content.browser.JavaBridgeCoercionTest.testPassJavaObject()  At JavaBridgeCoercionTest.java
 M C CSM: Shouldn't use synchronized method, please narrow down the synchronization scope.  At JavaBridgeArrayCoercionTest.java
 M C CSM: Shouldn't use synchronized method, please narrow down the synchronization scope.  At JavaBridgeArrayTest.java
 M C CSM: Shouldn't use synchronized method, please narrow down the synchronization scope.  At JavaBridgeBasicsTest.java