Add support for webapk without runtimeHost

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/ChooseHostBrowserDialog.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.webapk.shell_apk;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.view.ContextThemeWrapper;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.ImageView;
+import android.widget.ListView;
+import android.widget.TextView;
+
+import java.util.List;
+
+/**
+ * Shows the dialog to choose a host browser to launch WebAPK. Calls the listener callback when the
+ * host browser is chosen.
+ */
+

[Ted C, 2017/06/05 18:24:49]

remove blank line

[Xi Han, 2017/06/05 20:30:02]

Done.

+public class ChooseHostBrowserDialog {
+    /**
+     * A listener to receive updates when user chooses a host browser for the WebAPK, or dismiss the
+     * dialog.
+     */
+    public interface DialogListener {
+        void onHostBrowserSelected(String packageName);
+        void onQuit();
+    }
+
+    /** Listens to which browser is chosen by the user to launch WebAPK. */
+    private DialogListener mListener;
+
+    /**
+     * Shows the dialog for choosing a host browser.
+     * @param activity The current activity in which to create the dialog.
+     * @param url URL of the WebAPK that is shown on the dialog.
+     */
+    public void show(Activity activity, String url) {
+        if (!(activity instanceof DialogListener)) {
+            throw new IllegalArgumentException(
+                    activity.toString() + " must implement DialogListener");
+        }
+
+        mListener = (DialogListener) activity;
+        final List<WebApkUtils.BrowserItem> browserItems =
+                WebApkUtils.getBrowserInfosForHostBrowserSelection(activity.getPackageManager());
+
+        // The dialog contains:
+        // 1) a description of the dialog.
+        // 2) a list of browsers for user to choose from.
+        View view =
+                LayoutInflater.from(activity).inflate(R.layout.choose_host_browser_dialog, null);
+        TextView desc = (TextView) view.findViewById(R.id.desc);
+        ListView browserList = (ListView) view.findViewById(R.id.browser_list);
+        desc.setText(activity.getString(R.string.choose_host_browser, url));
+        browserList.setAdapter(new BrowserArrayAdapter(activity, browserItems));
+
+        AlertDialog.Builder builder = new AlertDialog.Builder(new ContextThemeWrapper(

[Ted C, 2017/06/05 18:24:48]

let's add a comment about the context theme wrapper here being needed for pre-L.

From the internets, it looks like we could either use this or set
android:windowBackground to transparent / @null in our own custom theme. 
Neither one is clearly better than the other, so I think a comment is
sufficient.

[Xi Han, 2017/06/05 20:30:02]

Done.

+                activity, android.R.style.Theme_DeviceDefault_Light_Dialog));
+        builder.setTitle(activity.getString(R.string.choose_host_browser_dialog_title, url))
+                .setView(view)
+                .setNegativeButton(R.string.choose_host_browser_dialog_quit,
+                        new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                mListener.onQuit();
+                            }
+                        });
+
+        final AlertDialog dialog = builder.create();
+        browserList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
+            @Override
+            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+                WebApkUtils.BrowserItem browserItem = browserItems.get(position);
+                if (browserItem.supportWebApks()) {
+                    mListener.onHostBrowserSelected(browserItem.getPackageName());
+                    dialog.cancel();
+                }
+            }
+        });
+
+        dialog.show();
+    };
+
+    /** Item adaptor for the list of browsers. */
+    private static class BrowserArrayAdapter extends ArrayAdapter<WebApkUtils.BrowserItem> {
+        private List<WebApkUtils.BrowserItem> mBrowsers;
+        private LayoutInflater mLayoutInflater;
+
+        public BrowserArrayAdapter(Context context, List<WebApkUtils.BrowserItem> browsers) {
+            super(context, R.layout.choose_host_browser_dialog_list, browsers);
+            mLayoutInflater = LayoutInflater.from(context);
+            mBrowsers = browsers;
+        }
+
+        @Override
+        public View getView(int position, View convertView, ViewGroup parent) {
+            if (convertView == null) {
+                convertView =
+                        mLayoutInflater.inflate(R.layout.choose_host_browser_dialog_list, null);
+            }
+
+            TextView name = (TextView) convertView.findViewById(R.id.browser_name);
+            ImageView icon = (ImageView) convertView.findViewById(R.id.browser_icon);
+            WebApkUtils.BrowserItem item = mBrowsers.get(position);
+
+            name.setText(item.getApplicationName());
+            name.setEnabled(item.supportWebApks());
+            icon.setImageDrawable(item.getApplicationIcon());
+            icon.setEnabled(item.supportWebApks());
+            return convertView;
+        }
+
+        @Override
+        public boolean isEnabled(int position) {
+            return mBrowsers.get(position).supportWebApks();
+        }
+    }
+}