Add support for webapk without runtimeHost

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java

Index: chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java
diff --git a/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java b/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java
index 4096cdc427006ea2b62cd292d7c1146df61c3a87..bc8c754d6fd63be19c5028d606cc9fb6465fd055 100644
--- a/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java
+++ b/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java
@@ -5,23 +5,89 @@
 package org.chromium.webapk.shell_apk;
 
 import android.content.Context;
+import android.content.Intent;
+import android.content.SharedPreferences;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.pm.ResolveInfo;
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
+import android.text.TextUtils;
 
+import org.chromium.webapk.lib.common.WebApkConstants;
 import org.chromium.webapk.lib.common.WebApkMetaDataKeys;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
 /**
  * Contains utility methods for interacting with WebAPKs.
  */
 public class WebApkUtils {
+    public static final String SHARED_PREF_RUNTIME_HOST = "runtime_host";
+
+    /**
+     * The package names of the channels of Chrome that support WebAPKs. The most preferred one
+     * comes first.
+     */
+    private static List<String> sBrowsersSupportingWebApk = new ArrayList<String>(
+            Arrays.asList("com.google.android.apps.chrome", "com.android.chrome", "com.chrome.beta",
+                    "com.chrome.dev", "com.chrome.canary"));
+
+    /** Stores information about a potential host browser for the WebAPK. */
+    public static class BrowserItem {
+        private String mPackageName;
+        private CharSequence mApplicationLabel;
+        private Drawable mIcon;
+        private boolean mSupportsWebApks;
+
+        public BrowserItem(String packageName, CharSequence applicationLabel, Drawable icon,
+                boolean supportsWebApks) {
+            mPackageName = packageName;
+            mApplicationLabel = applicationLabel;
+            mIcon = icon;
+            mSupportsWebApks = supportsWebApks;
+        }
+
+        /** Returns the package name of a browser. */
+        public String getPackageName() {
+            return mPackageName;
+        }
+
+        /** Returns the application name of a browser. */
+        public CharSequence getApplicationName() {
+            return mApplicationLabel;
+        }
+
+        /** Returns a drawable of the browser icon. */
+        public Drawable getApplicationIcon() {
+            return mIcon;
+        }
+
+        /** Returns whether the browser supports WebAPKs. */
+        public boolean supportsWebApks() {
+            return mSupportsWebApks;
+        }
+    }
 
     /**
-     * Caches the value read from Application Metadata which specifies the host browser's package
-     * name.
+     * Caches the package name of the host browser. {@link sHostPackage} might refer to a browser
+     * which has been uninstalled. A notification can keep the WebAPK process alive after the host
+     * browser has been uninstalled.
      */
     private static String sHostPackage;
 
+    /** For testing only. */
+    public static void resetCachedHostPackageForTesting() {
+        sHostPackage = null;
+    }
+
     /**
      * Returns a Context for the host browser that was specified when building the WebAPK.
      * @param context A context.
@@ -31,8 +97,7 @@ public class WebApkUtils {
         try {
             String hostPackage = getHostBrowserPackageName(context);
             return context.getApplicationContext().createPackageContext(
-                            hostPackage,
-                            Context.CONTEXT_IGNORE_SECURITY | Context.CONTEXT_INCLUDE_CODE);
+                    hostPackage, Context.CONTEXT_IGNORE_SECURITY | Context.CONTEXT_INCLUDE_CODE);
         } catch (NameNotFoundException e) {
             e.printStackTrace();
         }
@@ -40,15 +105,19 @@ public class WebApkUtils {
     }
 
     /**
-     * Returns the package name for the host browser that was specified when building the WebAPK.
+     * Returns the package name of the host browser to launch the WebAPK. Also caches the package
+     * name in the SharedPreference if it is not null.
      * @param context A context.
      * @return The package name. Returns null on an error.
      */
     public static String getHostBrowserPackageName(Context context) {
-        if (sHostPackage != null) return sHostPackage;
-        String hostPackage = readMetaDataFromManifest(context, WebApkMetaDataKeys.RUNTIME_HOST);
-        // Set {@link sHostPackage} to a non-null value so that the value is computed only once.
-        sHostPackage = hostPackage != null ? hostPackage : "";
+        if (sHostPackage == null) {
+            sHostPackage = getHostBrowserPackageNameInternal(context);
+            if (sHostPackage != null) {
+                writeHostBrowserToSharedPref(context, sHostPackage);
+            }
+        }
+
         return sHostPackage;
     }
 
@@ -64,6 +133,84 @@ public class WebApkUtils {
         return ai.metaData.getString(key);
     }
 
+    /**
+     * Returns the package name of the host browser to launch the WebAPK, or null if we did not find
+     * one.
+     */
+    private static String getHostBrowserPackageNameInternal(Context context) {
+        Set<String> installedBrowsers = getInstalledBrowsers(context.getPackageManager());
+        if (installedBrowsers.isEmpty()) {
+            return null;
+        }
+
+        // Gets the package name of the host browser if it is stored in the SharedPreference.
+        String cachedHostBrowser = getHostBrowserFromSharedPreference(context);
+        if (!TextUtils.isEmpty(cachedHostBrowser)
+                && installedBrowsers.contains(cachedHostBrowser)) {
+            return cachedHostBrowser;
+        }
+
+        // Gets the package name of the host browser if it is specified in AndroidManifest.xml.
+        String hostBrowserFromManifest =
+                readMetaDataFromManifest(context, WebApkMetaDataKeys.RUNTIME_HOST);
+        if (!TextUtils.isEmpty(hostBrowserFromManifest)) {
+            if (installedBrowsers.contains(hostBrowserFromManifest)) {
+                return hostBrowserFromManifest;
+            }
+            return null;
+        }
+
+        // Gets the package name of the default browser on the Android device.
+        // TODO(hanxi): Investigate the best way to know which browser supports WebAPKs.
+        String defaultBrowser = getDefaultBrowserPackageName(context.getPackageManager());
+        if (!TextUtils.isEmpty(defaultBrowser) && installedBrowsers.contains(defaultBrowser)
+                && sBrowsersSupportingWebApk.contains(defaultBrowser)) {
+            return defaultBrowser;
+        }
+
+        return null;
+    }
+
+    /**
+     * Returns a list of browsers to choose host browser from. The list includes all the installed
+     * browsers, and if none of the installed browser supports WebAPKs, Chrome will be added to the
+     * list as well.
+     */
+    public static List<BrowserItem> getBrowserInfosForHostBrowserSelection(
+            PackageManager packageManager) {
+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        List<ResolveInfo> resolvedActivityList = packageManager.queryIntentActivities(
+                browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+
+        boolean hasBrowserSupportingWebApks = false;
+        List<BrowserItem> browsers = new ArrayList<>();
+        for (ResolveInfo info : resolvedActivityList) {
+            boolean supportsWebApk = false;
+            if (sBrowsersSupportingWebApk.contains(info.activityInfo.packageName)) {
+                supportsWebApk = true;
+                hasBrowserSupportingWebApks = true;
+            }
+            browsers.add(new BrowserItem(info.activityInfo.packageName,
+                    info.loadLabel(packageManager), info.loadIcon(packageManager), supportsWebApk));
+        }
+
+        Collections.sort(browsers, new Comparator<BrowserItem>() {
+            @Override
+            public int compare(BrowserItem a, BrowserItem b) {
+                if (a.mSupportsWebApks == b.mSupportsWebApks) {
+                    return a.getPackageName().compareTo(b.getPackageName());
+                }
+                return a.mSupportsWebApks ? -1 : 1;
+            }
+        });
+
+        if (hasBrowserSupportingWebApks) return browsers;
+
+        // TODO(hanxi): add Chrome's icon to WebAPKs.
+        browsers.add(new BrowserItem("com.android.chrome", "Chrome", null, true));
+        return browsers;
+    }
+
     /**
      * Returns the uid for the host browser that was specified when building the WebAPK.
      * @param context A context.
@@ -84,4 +231,58 @@ public class WebApkUtils {
         }
         return -1;
     }
+
+    /** Returns the package name of the host browser cached in the SharedPreferences. */
+    public static String getHostBrowserFromSharedPreference(Context context) {
+        SharedPreferences sharedPref =
+                context.getSharedPreferences(WebApkConstants.PREF_PACKAGE, Context.MODE_PRIVATE);
+        return sharedPref.getString(SHARED_PREF_RUNTIME_HOST, null);
+    }
+
+    /** Returns a set of package names of all the installed browsers on the device. */
+    public static Set<String> getInstalledBrowsers(PackageManager packageManager) {
+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        List<ResolveInfo> resolvedActivityList = packageManager.queryIntentActivities(
+                browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+
+        Set<String> packagesSupportingWebApks = new HashSet<String>();
+        for (ResolveInfo info : resolvedActivityList) {
+            packagesSupportingWebApks.add(info.activityInfo.packageName);
+        }
+        return packagesSupportingWebApks;
+    }
+
+    /** Returns the package name of the default browser on the Android device. */
+    private static String getDefaultBrowserPackageName(PackageManager packageManager) {
+        Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://"));
+        ResolveInfo resolveInfo =
+                packageManager.resolveActivity(browserIntent, PackageManager.MATCH_DEFAULT_ONLY);
+        if (resolveInfo == null || resolveInfo.activityInfo == null) return null;
+
+        return resolveInfo.activityInfo.packageName;
+    }
+
+    /**
+     * Writes the package name of the host browser to the SharedPreferences. If the host browser is
+     * different than the previous one stored, delete the SharedPreference before storing the new
+     * host browser.
+     */
+    public static void writeHostBrowserToSharedPref(Context context, String hostPackage) {
+        if (TextUtils.isEmpty(hostPackage)) return;
+
+        SharedPreferences sharedPref =
+                context.getSharedPreferences(WebApkConstants.PREF_PACKAGE, Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = sharedPref.edit();
+        editor.putString(SHARED_PREF_RUNTIME_HOST, hostPackage);
+        editor.apply();
+    }
+
+    /** Deletes the SharedPreferences. */
+    public static void deleteSharedPref(Context context) {
+        SharedPreferences sharedPref =
+                context.getSharedPreferences(WebApkConstants.PREF_PACKAGE, Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = sharedPref.edit();
+        editor.clear();
+        editor.apply();
+    }
 }