Destroy the old RenderWidgetHostView when swapping out a main frame.

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 19f96d6a93448a19c60bdc20d14236fde6258d66..500c88772cd90b0fdacd08e946d2ee245c7834cf 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -8562,4 +8562,30 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
   EXPECT_EQ(expected_title, title_watcher.WaitAndGetTitle());
 }
 
+// This tests that we don't hide the RenderViewHost when reusing the
+// RenderViewHost for a subframe. See https://crbug.com/638375.
+IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest, ReusedRenderViewNotHidden) {
+  GURL a_url(embedded_test_server()->GetURL("a.com", "/title1.html"));
+  GURL b_url_a_subframe(embedded_test_server()->GetURL(
+      "b.com", "/cross_site_iframe_factory.html?b(a)"));
+
+  EXPECT_TRUE(NavigateToURL(shell(), a_url));
+
+  // Open a popup in a.com.
+  Shell* popup = OpenPopup(shell(), a_url, "popup");
+
+  // Navigate this popup to b.com with an a.com subframe.
+  EXPECT_TRUE(NavigateToURL(popup, b_url_a_subframe));
+
+  FrameTreeNode* root = static_cast<WebContentsImpl*>(popup->web_contents())
+                            ->GetFrameTree()
+                            ->root();
+  FrameTreeNode* child_node = root->child_at(0);
+
+  EXPECT_FALSE(child_node->current_frame_host()
+                   ->render_view_host()
+                   ->GetWidget()
+                   ->is_hidden());
+}
+
 }  // namespace content