Launch Chrome in non-WebAPK mode if WebAPK runtime library cannot be loaded

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

Index: chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/MainActivity.java
diff --git a/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/MainActivity.java b/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/MainActivity.java
index 012c4c61e96bd8c179d153991596cdb70bf98d69..52b1b1faf88ef43922a1f06016e6def098856895 100644
--- a/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/MainActivity.java
+++ b/chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/MainActivity.java
@@ -7,9 +7,16 @@ package org.chromium.webapk.shell_apk;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.net.Uri;
 import android.os.Bundle;
 import android.util.Log;
 
+import org.chromium.webapk.lib.common.WebApkConstants;
+import org.chromium.webapk.lib.common.WebApkUtils;
+
 import java.lang.reflect.Method;
 
 /**
@@ -24,6 +31,14 @@ public class MainActivity extends Activity {
     private static final String HOST_BROWSER_LAUNCHER_CLASS_NAME =
             "org.chromium.webapk.lib.runtime_library.HostBrowserLauncher";
 
+    // Must stay in sync with
+    // {@link org.chromium.chrome.browser.ShortcutHelper#REUSE_URL_MATCHING_TAB_ELSE_NEW_TAB}.
+    private static final String REUSE_URL_MATCHING_TAB_ELSE_NEW_TAB =
+            "REUSE_URL_MATCHING_TAB_ELSE_NEW_TAB";
+
+    // Key for start URL in Android Manifest.
+    private static final String META_DATA_START_URL = "startUrl";
+
     /**
      * Key for passing app icon id.
      */
@@ -32,19 +47,23 @@ public class MainActivity extends Activity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        launchHostBrowser();
+        if (!launchHostBrowserInWebApkMode()) {
+            // Launch browser in non-WebAPK mode.
+            launchHostBrowser();
+        }
         finish();
     }
 
     /**
      * Launches host browser in WebAPK mode.
+     * @return True if successful.
      */
-    public void launchHostBrowser() {
+    public boolean launchHostBrowserInWebApkMode() {
         ClassLoader webApkClassLoader = HostBrowserClassLoader.getClassLoaderInstance(
                 this, HOST_BROWSER_LAUNCHER_CLASS_NAME);
         if (webApkClassLoader == null) {
             Log.w(TAG, "Unable to create ClassLoader.");
-            return;
+            return false;
         }
 
         try {
@@ -56,9 +75,46 @@ public class MainActivity extends Activity {
             Bundle bundle = new Bundle();
             bundle.putInt(KEY_APP_ICON_ID, R.drawable.app_icon);
             launchMethod.invoke(hostBrowserLauncherInstance, this, getIntent(), bundle);
+            return true;
         } catch (Exception e) {
             Log.w(TAG, "Unable to launch browser in WebAPK mode.");
             e.printStackTrace();
+            return false;
+        }
+    }
+
+    /**
+     * Launches host browser in non-WebAPK mode.
+     */
+    public void launchHostBrowser() {
+        String startUrl = getStartUrl();
+        if (startUrl == null) {
+            return;
+        }
+        int source = getIntent().getIntExtra(WebApkConstants.EXTRA_SOURCE, 0);
+        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(startUrl));
+        intent.setPackage(WebApkUtils.getHostBrowserPackageName(this));
+        intent.putExtra(REUSE_URL_MATCHING_TAB_ELSE_NEW_TAB, true)
+              .putExtra(WebApkConstants.EXTRA_SOURCE, source);
+        startActivity(intent);
+    }
+
+    /**
+     * Returns the URL that the browser should navigate to.
+     */
+    public String getStartUrl() {
+        String overrideUrl = getIntent().getDataString();
+        if (overrideUrl != null && overrideUrl.startsWith("https:")) {
+            return overrideUrl;
+        }
+
+        ApplicationInfo appInfo;
+        try {
+            appInfo = getPackageManager().getApplicationInfo(
+                    getPackageName(), PackageManager.GET_META_DATA);
+        } catch (NameNotFoundException e) {
+            return null;
         }
+        return appInfo.metaData.getString(META_DATA_START_URL);
     }
 }