Make gfx::Rect class operations consistently mutate the class they are called on.

webkit/plugins/webview_plugin.cc

Index: webkit/plugins/webview_plugin.cc
diff --git a/webkit/plugins/webview_plugin.cc b/webkit/plugins/webview_plugin.cc
index 7d3dc7ed0281bc7f6afd452a74b8568e0ed185f7..9888b737ebf8a4962171a81027a44f196b6b395d 100644
--- a/webkit/plugins/webview_plugin.cc
+++ b/webkit/plugins/webview_plugin.cc
@@ -120,7 +120,8 @@ bool WebViewPlugin::getFormValue(WebString& value) {
 }
 
 void WebViewPlugin::paint(WebCanvas* canvas, const WebRect& rect) {
-  gfx::Rect paintRect(rect_.Intersect(rect));
+  gfx::Rect paintRect = rect_;
+  paintRect.Intersect(rect);
   if (paintRect.IsEmpty())
     return;