Add test to ensure that URLs that redirect inside the PDF plugin fail to load

chrome/browser/pdf/pdf_extension_test.cc

Index: chrome/browser/pdf/pdf_extension_test.cc
diff --git a/chrome/browser/pdf/pdf_extension_test.cc b/chrome/browser/pdf/pdf_extension_test.cc
index 118da0eb14645ffc82b6a45bc2101669ca25a353..a8dec4f8bdd4421c4285d1dca43537247b7c7d5e 100644
--- a/chrome/browser/pdf/pdf_extension_test.cc
+++ b/chrome/browser/pdf/pdf_extension_test.cc
@@ -910,3 +910,10 @@ IN_PROC_BROWSER_TEST_F(PDFExtensionTest, LinkShiftLeftClick) {
   const GURL& url = active_web_contents->GetURL();
   ASSERT_EQ(std::string("http://www.example.com/"), url.spec());
 }
+
+// Test that if the plugin tries to load a URL that redirects then it will fail
+// to load. This is to avoid the source origin of the document changing during
+// the redirect, which can have security implications. https://crbug.com/653749.
+IN_PROC_BROWSER_TEST_F(PDFExtensionTest, RedirectsFailInPlugin) {
+  RunTestsInFile("redirects_fail_test.js", "test.pdf");
+}