[Android WebView] Implement initial settings and callback support for Service Workers.

android_webview/java/src/org/chromium/android_webview/AwServiceWorkerClient.java

Index: android_webview/java/src/org/chromium/android_webview/AwServiceWorkerClient.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwServiceWorkerClient.java b/android_webview/java/src/org/chromium/android_webview/AwServiceWorkerClient.java
new file mode 100644
index 0000000000000000000000000000000000000000..cbfe3d01ecfff16341bc936d08e3a6a54593f5a3
--- /dev/null
+++ b/android_webview/java/src/org/chromium/android_webview/AwServiceWorkerClient.java
@@ -0,0 +1,18 @@
+// 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.android_webview;
+
+import org.chromium.android_webview.AwContentsClient.AwWebResourceRequest;
+
+/**
+ * Abstract base class that implementors of service worker related callbacks
+ * derive from.
+ */
+public abstract class AwServiceWorkerClient {
+
+    public abstract AwWebResourceResponse shouldInterceptRequest(AwWebResourceRequest request);
+
+    // TODO: add support for onReceivedError and onReceivedHttpError callbacks.
+}