Don't create unnecessary OOPIFs for subframe navigations that don't require a dedicated process.

chrome/browser/extensions/process_manager_browsertest.cc

Index: chrome/browser/extensions/process_manager_browsertest.cc
diff --git a/chrome/browser/extensions/process_manager_browsertest.cc b/chrome/browser/extensions/process_manager_browsertest.cc
index adaf411010263d70ef6491d0d12833856fa99f96..e7022f06e2cc2280670ba217982ce1157f3df1e4 100644
--- a/chrome/browser/extensions/process_manager_browsertest.cc
+++ b/chrome/browser/extensions/process_manager_browsertest.cc
@@ -1220,4 +1220,55 @@ IN_PROC_BROWSER_TEST_F(ProcessManagerBrowserTest,
   VerifyPostMessageToOpener(popup->GetMainFrame(), extension_frame);
 }
 
+// Test that when a web site has an extension iframe, navigating that iframe to
+// a different web site without --site-per-process will place it in the parent
+// frame's process.  See https://crbug.com/711006.
+IN_PROC_BROWSER_TEST_F(ProcessManagerBrowserTest,

[Charlie Reis, 2017/04/14 16:57:05]

Yep, makes sense to put this here for now, since I'm not sure how to encounter
this situation within content.  Once we start adding the ability to isolate
individual sites to content, we should probably add an equivalent test there.

[alexmos, 2017/04/17 17:36:02]

Acknowledged, and in fact I've already got that test written as part of my
origin isolation CL that's coming soon. :)

+                       ExtensionFrameNavigatesToParentSiteInstance) {
+  // This test matters only *without* --site-per-process.
+  if (content::AreAllSitesIsolatedForTesting())
+    return;
+
+  host_resolver()->AddRule("*", "127.0.0.1");
+
+  // Create a simple extension without a background page.
+  const Extension* extension = CreateExtension("Extension", false);
+  embedded_test_server()->ServeFilesFromDirectory(extension->path());
+  ASSERT_TRUE(embedded_test_server()->Start());
+
+  // Navigate main tab to a web page with a blank iframe.  There should be no
+  // extension frames yet.
+  NavigateToURL(embedded_test_server()->GetURL("a.com", "/blank_iframe.html"));
+  ProcessManager* pm = ProcessManager::Get(profile());
+  EXPECT_EQ(0u, pm->GetAllFrames().size());
+  EXPECT_EQ(0u, pm->GetRenderFrameHostsForExtension(extension->id()).size());
+
+  content::WebContents* tab =
+      browser()->tab_strip_model()->GetActiveWebContents();
+
+  // Navigate subframe to an extension URL.  This should go into a new
+  // extension process.
+  const GURL extension_url(extension->url().Resolve("empty.html"));
+  EXPECT_TRUE(content::NavigateIframeToURL(tab, "frame0", extension_url));
+  EXPECT_EQ(1u, pm->GetRenderFrameHostsForExtension(extension->id()).size());
+  EXPECT_EQ(1u, pm->GetAllFrames().size());
+
+  content::RenderFrameHost* main_frame = tab->GetMainFrame();
+  {
+    content::RenderFrameHost* subframe = ChildFrameAt(main_frame, 0);
+    EXPECT_NE(subframe->GetProcess(), main_frame->GetProcess());
+    EXPECT_NE(subframe->GetSiteInstance(), main_frame->GetSiteInstance());
+  }
+
+  // Navigate subframe to b.com.  This should be brought back to the parent
+  // frame's (a.com) process.
+  GURL b_url(embedded_test_server()->GetURL("b.com", "/empty.html"));
+  EXPECT_TRUE(content::NavigateIframeToURL(tab, "frame0", b_url));
+  {
+    content::RenderFrameHost* subframe = ChildFrameAt(main_frame, 0);
+    EXPECT_EQ(subframe->GetProcess(), main_frame->GetProcess());
+    EXPECT_EQ(subframe->GetSiteInstance(), main_frame->GetSiteInstance());
+  }
+}
+
 }  // namespace extensions