Browser test that demonstrates failure to run subframe unload handlers.

content/browser/site_per_process_browsertest.cc

Index: content/browser/site_per_process_browsertest.cc
diff --git a/content/browser/site_per_process_browsertest.cc b/content/browser/site_per_process_browsertest.cc
index 80c4d169bf440321d0aa58edef178fe177dd45d4..45960c266237ab809fa741d256f7fede17f6eb78 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -3367,6 +3367,35 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest, LoadEventForwarding) {
   }
 }
 
+IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest, SetCookieInSubframeUnload) {
+  GURL url = embedded_test_server()->GetURL(
+      "a.com", "/onunload_cookie_wrapper_wrapper.html");
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  FrameTreeNode* root = web_contents()->GetFrameTree()->root();
+  EXPECT_EQ(
+      " Site A ------------ proxies for B\n"
+      "   +--Site B ------- proxies for A\n"
+      "        +--Site B -- proxies for A\n"
+      "Where A = http://a.com/\n"
+      "      B = http://b.com/",
+      DepictFrameTree(root));
+
+  NavigateFrameToURL(root->child_at(0),
+                     embedded_test_server()->GetURL("c.com", "/title1.html"));
+
+  EXPECT_EQ(
+      " Site A ------------ proxies for C\n"
+      "   +--Site C ------- proxies for A\n"
+      "Where A = http://a.com/\n"
+      "      C = http://c.com/",
+      DepictFrameTree(root));
+  EXPECT_EQ("",
+            content::GetCookies(shell()->web_contents()->GetBrowserContext(),
+                                embedded_test_server()->GetURL(
+                                    "b.com", "/onunload_cookie.html")));
+}
+
 // Check that postMessage can be routed between cross-site iframes.
 IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest, SubframePostMessage) {
   GURL main_url(embedded_test_server()->GetURL(