Swap the main frame in --site-per-process mode too.

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 ca329520745dd2e6e75fcee9ddfa7d987544aa61..3f6c993a90a44c7938d1ebb4bcd98870c50841a3 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -2312,4 +2312,38 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest, RFPHDestruction) {
       DepictFrameTree(root));
 }
 
+IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,

[nasko, 2015/05/06 22:57:44]

nit: It will be useful to add a description of what this test case is trying to
verify. As it is, I can see what it does, but don't know much of why it does it
and what it ensures.

[dcheng, 2015/05/07 22:30:13]

Done.

+                       OpenCrossSiteWindowWithFrames) {
+  ASSERT_EQ(1u, Shell::windows().size());
+  Shell* main_window = Shell::windows()[0];
+
+  // Navigate the main window.
+  GURL main_url(embedded_test_server()->GetURL("/site_per_process_main.html"));
+  NavigateToURL(main_window, main_url);
+  EXPECT_EQ(main_window->web_contents()->GetLastCommittedURL(), main_url);
+
+  // Load a cross-site page into a new window.
+  GURL cross_url =
+      embedded_test_server()->GetURL("foo.com", "/site_per_process_main.html");
+  std::string script = "window.open('" + cross_url.spec() + "')";
+  EXPECT_TRUE(ExecuteScript(main_window->web_contents(), script));
+  ASSERT_EQ(2u, Shell::windows().size());
+  Shell* cross_window = Shell::windows()[1];
+  WaitForLoadStop(cross_window->web_contents());
+  EXPECT_EQ(cross_window->web_contents()->GetLastCommittedURL(), cross_url);
+
+  // Make sure the main window is still live. To create a synchronization point
+  // and ensure that the renderer has processed all the messages for updating
+  // the frame tree, execute a simple bit of JS first.
+  EXPECT_TRUE(ExecuteScript(main_window->web_contents(), "true"));
+  EXPECT_TRUE(static_cast<WebContentsImpl*>(main_window->web_contents())
+                  ->GetMainFrame()
+                  ->IsRenderFrameLive());
+  // And check the cross-site window too.
+  EXPECT_TRUE(ExecuteScript(cross_window->web_contents(), "true"));
+  EXPECT_TRUE(static_cast<WebContentsImpl*>(cross_window->web_contents())
+                  ->GetMainFrame()
+                  ->IsRenderFrameLive());
+}
+
 }  // namespace content