Fix: long-tapping a WebAPK in recents shows Chrome.

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 64906a676c9cfc65600c40023b17160cce71b088..f22ba58e323f9e7bab811d4195f346b1677fec04 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
@@ -40,6 +40,12 @@ public class WebappLauncherActivity extends Activity {
 
     private static final String TAG = "webapps";
 
+    /**
+     * We remove android:documentLaunchMode="intoExisting" attribute from WebApkActivity since this
+     * version.
+     */
+    private static final int SHELL_APK_VERSION_BEFORE_REMOVE_DOCUMENT_LAUNCH_MODE = 1;
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -149,9 +155,20 @@ public class WebappLauncherActivity extends Activity {
         launchIntent.setAction(Intent.ACTION_VIEW);
         launchIntent.setData(Uri.parse(WebappActivity.WEBAPP_SCHEME + "://" + info.id()));
 
-        if (!isWebApk) {
-            // For WebAPK, we don't start a new task for WebApkActivity, it is just on top
-            // of the WebAPK's main activity and in the same task.
+        if (isWebApk && info instanceof WebApkInfo) {
+            // Since shell APK version 2, we removes the android:documentLaunchMode="intoExisting"
+            // attribute from WebApkActivity. Instead, flag {@link FLAG_ACTIVITY_CLEAR_TOP} is used
+            // to deliver this intent to the WebApkActivity instance if it is already running on the
+            // top of the stack via onNewIntent(). WebApkActivity should be on top of the WebAPK's
+            // main activity in the same task stack. See crbug.com/700157.
+            if (((WebApkInfo) info).shellApkVersion()
+                    > SHELL_APK_VERSION_BEFORE_REMOVE_DOCUMENT_LAUNCH_MODE) {
+                launchIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
+            } else {
+                launchIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
+                        | ApiCompatibilityUtils.getActivityNewDocumentFlag());
+            }
+        } else {
             launchIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
                     | ApiCompatibilityUtils.getActivityNewDocumentFlag());