Always call WebView.onPageStarted(), regardless of whether a WebViewClient has been set

This makes sure that the page's SSL certificate is cleared when the page load
starts.

Follows on from https://android-git.corp.google.com/g/#/c/138147.

Bug: 5287216
Change-Id: I40f74a72dc495c48d7167b7b70a845a8481feb85

Author: Steve Block

core/java/android/webkit/CallbackProxy.java

@@ -905,11 +905,9 @@ public void startWait() {
     */
 
     public void onPageStarted(String url, Bitmap favicon) {
-        // Do an unsynchronized quick check to avoid posting if no callback has
-        // been set.
-        if (mWebViewClient == null) {
-            return;
-        }
+        // We need to send the message even if no WebViewClient is set, because we need to call
+        // WebView.onPageStarted().
+
         // Performance probe
         if (PERF_PROBE) {
             mWebCoreThreadTime = SystemClock.currentThreadTimeMillis();