Add client cert support to android_webview

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 34e6ca515336224ee93be5ad915c4b4a3b27dda0..d1dc1be5a686fcbbaa45761213a1fe9927f5aca0 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
@@ -17,12 +17,15 @@ import android.webkit.ValueCallback;
 import android.webkit.WebChromeClient;
 
 import org.chromium.android_webview.AwContentsClient;
+import org.chromium.android_webview.AwContentsClientBridge;
 import org.chromium.android_webview.AwHttpAuthHandler;
 import org.chromium.android_webview.InterceptedRequestData;
 import org.chromium.android_webview.JsPromptResultReceiver;
 import org.chromium.android_webview.JsResultReceiver;
 import org.chromium.base.ThreadUtils;
 
+import java.security.Principal;
+
 /**
  * As a convience for tests that only care about specefic callbacks, this class provides
  * empty implementations of all abstract methods.
@@ -87,6 +90,14 @@ public class NullContentsClient extends AwContentsClient {
     }
 
     @Override
+    public void onReceivedClientCertRequest(
+            final AwContentsClientBridge.ClientCertificateRequestCallback callback,
+            final String[] keyTypes, final Principal[] principals, final String host,
+            final int port) {
+        callback.proceed(null, null);
+    }
+
+    @Override
     public void onReceivedLoginRequest(String realm, String account, String args) {
     }