Upstream: Launch WebApkActivity from WebAPK.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
index c25ccaebbc11b28233f726ba673aa941fe847384..e16c6ba598322f54b0b856ff04ee0e9d4f342b94 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
@@ -13,14 +13,17 @@ import android.util.Base64;
 
 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.ApplicationStatus;
+import org.chromium.base.CommandLine;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
+import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.IntentHandler;
 import org.chromium.chrome.browser.ShortcutHelper;
 import org.chromium.chrome.browser.document.ChromeLauncherActivity;
 import org.chromium.chrome.browser.metrics.LaunchMetrics;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.util.IntentUtils;
+import org.chromium.webapk.lib.common.WebApkConstants;
 
 import java.lang.ref.WeakReference;
 
@@ -51,6 +54,7 @@ public class WebappLauncherActivity extends Activity {
         Intent intent = getIntent();
         String webappId = webappInfo.id();
         String webappUrl = webappInfo.uri().toString();
+        String webApkPackageName = webappInfo.webApkPackageName();
         int webappSource = webappInfo.source();
 
         if (webappId != null && webappUrl != null) {
@@ -67,6 +71,10 @@ public class WebappLauncherActivity extends Activity {
                     ContextUtils.getApplicationContext());
             boolean isUrlValid = (webappMac != null
                     && WebappAuthenticator.isUrlValid(this, webappUrl, webappMac));
+            boolean isValidWebApk = isValidWebApk(webApkPackageName);
+            if (webApkPackageName != null && !isValidWebApk) {
+                isUrlValid = false;
+            }
 
             if (isTrusted || isUrlValid) {
                 LaunchMetrics.recordHomeScreenLaunchIntoStandaloneActivity(webappUrl, webappSource);
@@ -98,8 +106,12 @@ public class WebappLauncherActivity extends Activity {
                 launchIntent.putExtra(ShortcutHelper.EXTRA_SOURCE, webappSource);
             }
 
-            launchIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
-                    | ApiCompatibilityUtils.getActivityNewDocumentFlag());
+            if (!isValidWebApk) {
+                // For WebAPK, we don't start a new task for WebappActivity, it is just on top
+                // of the WebAPK's main activity and in the same task.
+                launchIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
+                        | ApiCompatibilityUtils.getActivityNewDocumentFlag());
+            }
             startActivity(launchIntent);
         }
 
@@ -129,4 +141,17 @@ public class WebappLauncherActivity extends Activity {
 
         return false;
     }
+
+    /**
+     * Checks whether the package being targeted is a valid WebAPK.
+     * @param webapkPackageName The package name of the requested WebAPK.
+     * @return true iff all validation criteria are met.
+     */
+    private boolean isValidWebApk(String webapkPackageName) {
+        // TODO(hanxi): Adds more validation checks. For example, whether the WebAPK is signed
+        // by the WebAPK Minting Server.
+        return CommandLine.getInstance().hasSwitch(ChromeSwitches.ENABLE_WEBAPK)
+                && webapkPackageName != null
+                && webapkPackageName.startsWith(WebApkConstants.WEBAPK_PACKAGE_PREFIX);
+    }
 }