Add external intents for WebAPKs to Launch.HomescreenSource.

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 5a0b7d4ad695cdde432daec0b660ab4e1c15195f..e30875d3a331c1bbdfff0a3290f591ff735ed751 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
@@ -92,7 +92,11 @@ public class MainActivity extends Activity {
         Log.v(TAG, "Package name of the WebAPK:" + packageName);
 
         String runtimeHost = WebApkUtils.getHostBrowserPackageName(this);
+        boolean isFromExternalIntent = (overrideUrl != null);
         int source = getIntent().getIntExtra(WebApkConstants.EXTRA_SOURCE, 0);
+        if (isFromExternalIntent && source == WebApkConstants.SHORTCUT_SOURCE_UNKNOWN) {
+            source = WebApkConstants.SHORTCUT_SOURCE_EXTERNAL_INTENT;
+        }
 
         // The override URL is non null when the WebAPK is launched from a deep link. The WebAPK
         // should navigate to the URL in the deep link even if the WebAPK is already open.
@@ -102,7 +106,7 @@ public class MainActivity extends Activity {
         intent.putExtra(WebApkConstants.EXTRA_URL, startUrl)
                 .putExtra(WebApkConstants.EXTRA_SOURCE, source)
                 .putExtra(WebApkConstants.EXTRA_WEBAPK_PACKAGE_NAME, packageName)
-                .putExtra(WebApkConstants.EXTRA_WEBAPK_FORCE_NAVIGATION, (overrideUrl != null));
+                .putExtra(WebApkConstants.EXTRA_WEBAPK_FORCE_NAVIGATION, isFromExternalIntent);
 
         try {
             startActivity(intent);