Add a chrome://webapks page.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInfoCallback.java

+// Copyright 2017 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.webapps;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.ShortcutHelper;
+
+/** A simple callback to load the information on WebAPKs. */
+public class WebApkInfoCallback {
+    private long mNativeWebApkInfoCallback;
+
+    /**
+     * Fetches the information of all WebAPKs installed on the device and returns them to the
+     * caller using a callback.
+     *
+     * @param webApkInfoCallback Callback to be called with each WebAPK found on the device.
+     */
+    @CalledByNative
+    private static void listWebApks(WebApkInfoCallback webApkInfoCallback) {
+        ShortcutHelper.listWebApks(webApkInfoCallback);
+    }
+
+    /**
+     * Called with information of one WebAPK. When information is requested, it will be called once
+     * for each WebAPK installed on the device.
+     *
+     * @param name The name of the WebAPK.
+     * @param packageName The package name of the WebAPK.
+     * @param shellApkVersion The version of the shell APK of the WebAPK.
+     * @param versionCode The version code associated with the WebAPK.
+     */
+    public void onWebApkFound(
+            String name, String packageName, int shellApkVersion, int versionCode) {
+        nativeOnWebApkFound(
+                mNativeWebApkInfoCallback, name, packageName, shellApkVersion, versionCode);
+    }
+
+    /** Destroys the native counterpart of this object. */
+    public void destroy() {
+        nativeDestroy(mNativeWebApkInfoCallback);
+        mNativeWebApkInfoCallback = 0;
+    }
+
+    /**
+     * Called from C++ by |nativeWebApkInfoCallback| to instantiate this class. Note that this is
+     * the only way to construct an WebApkInfoCallback; the constructor is private.
+     * @param nativeWebApkInfoCallback The native counterpart that creates and owns this object.
+     */
+    @CalledByNative
+    private static WebApkInfoCallback create(long nativeWebApkInfoCallback) {
+        return new WebApkInfoCallback(nativeWebApkInfoCallback);
+    }
+
+    private WebApkInfoCallback(long nativeWebApkInfoCallback) {
+        mNativeWebApkInfoCallback = nativeWebApkInfoCallback;
+    }
+
+    private native void nativeOnWebApkFound(long nativeWebApkInfoCallback, String name,
+            String packageName, int shellApkVersion, int versionCode);
+    private native void nativeDestroy(long nativeWebApkInfoCallback);
+}