Move NullWebViewClient implementation to chromium layer

android_webview/test/shell/src/org/chromium/android_webview/test/NullContentsClient.java

Index: android_webview/test/shell/src/org/chromium/android_webview/test/NullContentsClient.java
diff --git a/android_webview/test/shell/src/org/chromium/android_webview/test/NullContentsClient.java b/android_webview/test/shell/src/org/chromium/android_webview/test/NullContentsClient.java
index 035ff4c12fa1eb024acc9876a97a00e912b06c7d..d4c6b3d9d6dc30a726e2b05c57af94c734014093 100644
--- a/android_webview/test/shell/src/org/chromium/android_webview/test/NullContentsClient.java
+++ b/android_webview/test/shell/src/org/chromium/android_webview/test/NullContentsClient.java
@@ -45,6 +45,11 @@ public class NullContentsClient extends AwContentsClient {
     }
 
     @Override
+    public boolean hasWebViewClient() {
+        return true;
+    }
+
+    @Override
     public boolean shouldOverrideUrlLoading(String url) {
         return false;
     }