Fix bug 5309557 - Monkeys and SIGSEGV do not mix!

Make sure that the native component of WebView has been initialized
before any native-level optimization involving window focus occurs.

Change-Id: I24ca5fe21657aeb1a1faf5bc36fba5ea11064f86

Author: adamp

core/java/android/webkit/WebView.java

@@ -5573,15 +5573,15 @@ public void onWindowFocusChanged(boolean hasWindowFocus) {
         setActive(hasWindowFocus);
         if (hasWindowFocus) {
             JWebCoreJavaBridge.setActiveWebView(this);
-            if (mPictureUpdatePausedForFocusChange) {
+            if (mPictureUpdatePausedForFocusChange && mNativeClass != 0) {
                 WebViewCore.resumeUpdatePicture(mWebViewCore);
                 nativeSetIsScrolling(false);
                 mPictureUpdatePausedForFocusChange = false;
             }
         } else {
             JWebCoreJavaBridge.removeActiveWebView(this);
             final WebSettings settings = getSettings();
-            if (settings != null && settings.enableSmoothTransition() &&
+            if (settings != null && settings.enableSmoothTransition() && mNativeClass != 0 &&
                     mWebViewCore != null && !WebViewCore.isUpdatePicturePaused(mWebViewCore)) {
                 WebViewCore.pauseUpdatePicture(mWebViewCore);
                 nativeSetIsScrolling(true);