Add external data use observer

chrome/android/java/src/org/chromium/chrome/browser/datausage/ExternalDataUseObserverAndroid.java

Index: chrome/android/java/src/org/chromium/chrome/browser/datausage/ExternalDataUseObserverAndroid.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/datausage/ExternalDataUseObserverAndroid.java b/chrome/android/java/src/org/chromium/chrome/browser/datausage/ExternalDataUseObserverAndroid.java
new file mode 100644
index 0000000000000000000000000000000000000000..a1ee3d4ca864ca1dd78685bdceea95711c9ba79a
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/datausage/ExternalDataUseObserverAndroid.java
@@ -0,0 +1,31 @@
+// Copyright 2015 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.chrome.browser.datausage;
+
+import android.content.Context;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.chrome.browser.ChromeApplication;
+
+/**
+ * This class provides a base class implementation of a data use observer that is external to
+ * Chromium. This class should be accessed only on IO thread.
+ */
+@JNINamespace("chrome::android")
+public class ExternalDataUseObserverAndroid {
+    @CalledByNative
+    private static ExternalDataUseObserverAndroid create(Context context, long nativePtr) {
+        return ((ChromeApplication) context).createExternalDataUseObserverAndroid(nativePtr);
+    }
+
+    @CalledByNative
+    private void onDataUse(String tag, long bytesDownloaded, long bytesUploaded) {}
+
+    /**
+     * Creates an instance of |@link #sExternalDataUseObserverAndroid}.

[newt (away), 2015/10/13 19:05:21]

This comment isn't correct

[tbansal1, 2015/10/13 21:30:21]

Done.

+     */
+    public ExternalDataUseObserverAndroid() {}
+}