Merge revision 449-452 changes:

- Linux: Fix window destruction crash.
- Linux: Fix cefclient shutdown crash.
- Remove WebURLRequestTest.CANCEL test with WUR_STATE_LOADING due to flakiness.
- Linux: Initialize the 'proxy_type' variable to make the compiler happy.

git-svn-id: https://chromiumembedded.googlecode.com/svn/branches/963@454 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/browser_impl.cc

@@ -786,8 +786,11 @@ void CefBrowserImpl::UIT_DestroyBrowser()
   }
 
   // Clean up anything associated with the WebViewHost widget.
-  UIT_GetWebViewHost()->webwidget()->close();
-  webviewhost_.reset();
+  if (webviewhost_.get()) {
+    if (webviewhost_->webwidget())
+      webviewhost_->webwidget()->close();
+    webviewhost_.reset();
+  }
 
   // Remove the reference added in UIT_CreateBrowser().
   Release();