Properly throw java exceptions from shouldOverrideUrlLoading

base/test/android/java/src/org/chromium/base/TestSystemMessageHandler.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base;
+
+import android.os.Message;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+/**
+ * Test-only message handler enabling us to test that Java exceptions thrown from a JNI call
+ * originating from the native side are propagated to the Message Handler (instead of causing a
+ * native crash).
+ * This class declares a custom exception and wraps the SystemMessageHandler message handling
+ * mechanism to catch such exceptions. When catching an exception we call the native side to notify
+ * tests that the correct exception was thrown and caught.
+ */
+@JNINamespace("base::android")
+class TestSystemMessageHandler extends SystemMessageHandler {
+    private long mWaitableTestEventNative;
+
+    private TestSystemMessageHandler(
+            long messagePumpDelegateNative, long messagePumpNative, long waitableTestEventNative) {
+        super(messagePumpDelegateNative, messagePumpNative);
+        mWaitableTestEventNative = waitableTestEventNative;
+    }
+
+    @Override
+    public void handleMessage(Message msg) {
+        try {
+            super.handleMessage(msg);
+        } catch (TestException e) {
+            nativeNotifyTestDone(mWaitableTestEventNative);
+            return;
+        }
+    }
+
+    private static class TestException extends RuntimeException {
+        TestException(String message) {
+            super(message);
+        }
+    }
+
+    @CalledByNative
+    private static TestSystemMessageHandler create(
+            long messagePumpDelegateNative, long messagePumpNative, long waitableTestEvent) {
+        return new TestSystemMessageHandler(
+                messagePumpDelegateNative, messagePumpNative, waitableTestEvent);
+    }
+
+    private static native void nativeNotifyTestDone(long messagePumpNative);
+}