Revert 252883 "Remove tests and code for showModalDialog"

content/browser/webkit_browsertest.cc

Index: content/browser/webkit_browsertest.cc
diff --git a/content/browser/webkit_browsertest.cc b/content/browser/webkit_browsertest.cc
index 1d33755ac58879a1894a4ab6b3d3cd1f12517aeb..5394f5bcc5564fc2ef8b6a2af350a4dc1b45683f 100644
--- a/content/browser/webkit_browsertest.cc
+++ b/content/browser/webkit_browsertest.cc
@@ -76,4 +76,19 @@ IN_PROC_BROWSER_TEST_F(WebKitBrowserTest, PrerenderNoCrash) {
   EXPECT_FALSE(shell()->web_contents()->IsCrashed());
 }
 
+// This is a browser test because DumpRenderTree doesn't run nested message
+// loops. The failure case was that a nested message triggered from an element
+// that has signalled an error but had an open request would receive a body for
+// the request and crash/fail an assertion.
+const char kErrorBodyNoCrash[] =
+    "files/error-body-no-crash.html";
+IN_PROC_BROWSER_TEST_F(WebKitBrowserTest, ErrorBodyNoCrash) {
+  ASSERT_TRUE(test_server()->Start());
+  GURL url = test_server()->GetURL(kErrorBodyNoCrash);
+
+  NavigateToURL(shell(), url);
+
+  EXPECT_FALSE(shell()->web_contents()->IsCrashed());
+}
+
 }  // namespace content