Revert of [Android:WebAPK] Don't add webapp to homescreen if WebAPK install times out part 2/3

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/GooglePlayWebApkInstallDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/GooglePlayWebApkInstallDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/GooglePlayWebApkInstallDelegate.java
index 87a5bf68d3509f06787a7c05ae2ce4af2b8e7b7e..2baaf903136b49134605c1071db9d2bca89af7dc 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/GooglePlayWebApkInstallDelegate.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/GooglePlayWebApkInstallDelegate.java
@@ -38,10 +38,10 @@
      * @param title The title of the WebAPK to display during installation.
      * @param token The token from WebAPK Minter Server.
      * @param url The start URL of the WebAPK to install.
-     * @param callback The callback to invoke when the install completes, times out or fails.
+     * @param callback The callback to invoke when the install is either completed or failed.
      */
     void installAsync(String packageName, int version, String title, String token, String url,
-            Callback<Integer> callback);
+            Callback<Boolean> callback);
 
     /**
      * Calls the callback once the installation either succeeded or failed.
@@ -49,4 +49,10 @@
      * @param event The result of the install.
      */
     void onGotInstallEvent(String packageName, @InstallerPackageEvent int event);
+
+    /**
+     * Checks whether Google Play Install API is available.
+     * @param callback The callback to invoke when the check is done.
+     */
+    void canInstallWebApk(Callback<Boolean> callback);
 }