Upstream: Initialize ChromeWebApkHost in WebappLaunchActivity.

chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java

Index: chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java
diff --git a/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java b/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java
index 3d9eb4a5f7aaa07878b0817ef08515fe287f0acd..a6b790cfa50f2b0bbcd82236ce712e1e3690413d 100644
--- a/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java
+++ b/chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java
@@ -26,6 +26,7 @@ public class WebApkValidator {
 
     private static final String TAG = "WebApkValidator";
     private static byte[] sExpectedSignature;
+    private static boolean sIsInitialized = false;
 
     /**
      * Queries the PackageManager to determine whether a WebAPK can handle the URL. Ignores
@@ -118,6 +119,10 @@ public class WebApkValidator {
      * @param expectedSignature
      */
     public static void initWithBrowserHostSignature(byte[] expectedSignature) {
+        if (sIsInitialized) {

[pkotwicz, 2016/06/10 21:34:14]

Can we return if sExpectedSignature != null ?

[Xi Han, 2016/06/13 20:10:53]

Done.

+            return;
+        }
         sExpectedSignature = Arrays.copyOf(expectedSignature, expectedSignature.length);
+        sIsInitialized = true;
     }
 }