Name the ScopedClosureRunner in XmlParsingDone(...).

This CL names the base::ScopedClosureRunner object in the XmlParsingDone
function. Previously, a temporary object was created, so the closure
would be called at the end of the expression. Naming the object ensures
it won't be called until the function ends.

Change-Id: I80805f85d15e75f287d169b381144c7fabbea1e7
Reviewed-on: https://chromium-review.googlesource.com/1037704Reviewed-by: Jay Civelli <jcivelli@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Andres Calderon Jaramillo <andrescj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555835}

chrome/browser/safe_xml_parser_browsertest.cc

@@ -73,7 +73,7 @@ class SafeXmlParserTest : public InProcessBrowserTest {
                       std::unique_ptr<base::Value> expected_value,
                       std::unique_ptr<base::Value> actual_value,
                       const base::Optional<std::string>& error) {
-    base::ScopedClosureRunner(std::move(quit_loop_closure));
+    base::ScopedClosureRunner runner(std::move(quit_loop_closure));
     if (!expected_value) {
       EXPECT_FALSE(actual_value);
       EXPECT_TRUE(error);