Fixing a monkey crash in the BrowserSettings

Monkey crash, sometimes the function getCurrentTopWebView()
can return null causing a crash in clearFormData().

Change-Id: I27d38fafd448a3922a09bbdf2b31ab6f78fecf88
diff --git a/src/com/android/browser/BrowserSettings.java b/src/com/android/browser/BrowserSettings.java
index 9c5af34..c3b6a08 100644
--- a/src/com/android/browser/BrowserSettings.java
+++ b/src/com/android/browser/BrowserSettings.java
@@ -515,7 +515,10 @@
     /* package */ void clearFormData(Context context) {
         WebViewDatabase.getInstance(context).clearFormData();
         if (mTabControl != null) {
-            mTabControl.getCurrentTopWebView().clearFormData();
+            WebView currentTopView = mTabControl.getCurrentTopWebView();
+            if (currentTopView != null) {
+                currentTopView.clearFormData();
+            }
         }
     }