fix history context menu bug

    http://b/issue?id=2953912

    Note: the bookmark status (star) is not correct
    and will be fixed separately

Change-Id: I20d1e52e9d6f6aeb7c0f1c66a61bed4d001e9092
diff --git a/src/com/android/browser/BrowserActivity.java b/src/com/android/browser/BrowserActivity.java
index 590235c..ff9a418 100644
--- a/src/com/android/browser/BrowserActivity.java
+++ b/src/com/android/browser/BrowserActivity.java
@@ -1627,6 +1627,9 @@
         if (v instanceof TitleBarBase) {
             return;
         }
+        if (!(v instanceof WebView)) {
+            return;
+        }
         WebView webview = (WebView) v;
         WebView.HitTestResult result = webview.getHitTestResult();
         if (result == null) {