Propagate inert state to OOPIFs when a modal dialog is active

content/browser/site_per_process_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/site_per_process_browsertest.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 10182 matching lines @@
 
   // Go back again.  This should go to foo.com.
   {
     TestNavigationObserver back_observer(web_contents());
     web_contents()->GetController().GoBack();
     back_observer.Wait();
   }
   EXPECT_EQ(foo_url, web_contents()->GetMainFrame()->GetLastCommittedURL());
 }
 
+// Class to sniff incoming IPCs for FrameHostMsg_SetIsInert messages.
+class SetIsInertMessageFilter : public content::BrowserMessageFilter {
+ public:
+  SetIsInertMessageFilter()
+      : content::BrowserMessageFilter(FrameMsgStart),
+        message_loop_runner_(new content::MessageLoopRunner),
+        msg_received_(false) {}
+
+  bool OnMessageReceived(const IPC::Message& message) override {
+    IPC_BEGIN_MESSAGE_MAP(SetIsInertMessageFilter, message)
+      IPC_MESSAGE_HANDLER(FrameHostMsg_SetIsInert, OnSetIsInert)
+    IPC_END_MESSAGE_MAP()
+    return false;
+  }
+
+  bool is_inert() const { return is_inert_; }
+
+  void Wait() { message_loop_runner_->Run(); }
+
+  void Reset() {

[alexmos, 2017/06/16 02:17:57]

Is this needed?  It doesn't appear to be used in the test.

[kenrb, 2017/06/19 19:26:22]

Removed.

+    is_inert_ = false;
+    message_loop_runner_ = new content::MessageLoopRunner;
+    msg_received_ = false;
+  }
+
+ private:
+  ~SetIsInertMessageFilter() override {}
+
+  void OnSetIsInert(bool is_inert) {
+    content::BrowserThread::PostTask(
+        content::BrowserThread::UI, FROM_HERE,
+        base::Bind(&SetIsInertMessageFilter::OnSetIsInertOnUI, this, is_inert));
+  }
+  void OnSetIsInertOnUI(bool is_inert) {
+    is_inert_ = is_inert;
+    if (!msg_received_) {
+      msg_received_ = true;
+      message_loop_runner_->Quit();
+    }
+  }
+  scoped_refptr<content::MessageLoopRunner> message_loop_runner_;
+  bool msg_received_;
+  bool is_inert_;
+  DISALLOW_COPY_AND_ASSIGN(SetIsInertMessageFilter);
+};
+
+// Tests that when a frame contains a modal <dialog> element, out-of-process
+// iframe children cannot take focus, because they are inert.
+IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest, CrossProcessInertSubframe) {
+  GURL main_url(embedded_test_server()->GetURL(
+      "a.com", "/cross_site_iframe_factory.html?a(b)"));
+  EXPECT_TRUE(NavigateToURL(shell(), main_url));
+
+  FrameTreeNode* root = static_cast<WebContentsImpl*>(shell()->web_contents())
+                            ->GetFrameTree()
+                            ->root();
+  ASSERT_EQ(1U, root->child_count());
+
+  FrameTreeNode* iframe_node = root->child_at(0);
+
+  EXPECT_TRUE(ExecuteScript(
+      iframe_node,
+      "document.head.innerHTML = '';"
+      "document.body.innerHTML = '<input id=\"text1\"> <input id=\"text2\">';"
+      "text1.focus();"));
+
+  scoped_refptr<SetIsInertMessageFilter> filter = new SetIsInertMessageFilter();
+  root->current_frame_host()->GetProcess()->AddFilter(filter.get());

[alexmos, 2017/06/16 02:17:57]

Perhaps mention in a comment somewhere that the inert message will be sent by
the proxy for b.com in a.com's process, and hence the filter is installed for
a.com.

[kenrb, 2017/06/19 19:26:22]

Done.

+
+  // Add a <dialog> to the root frame and call showModal on it.
+  EXPECT_TRUE(ExecuteScript(root,
+                            "let dialog = "
+                            "document.body.appendChild(document.createElement('"
+                            "dialog'));"
+                            "dialog.innerHTML = 'Modal dialog <input>';"
+                            "dialog.showModal();"));
+  filter->Wait();
+  EXPECT_TRUE(filter->is_inert());
+
+  // This yields the UI thread to ensure that the real SetIsInert message
+  // handler runs, in order to guarantee that the update arrives at the
+  // renderer process before the script below.
+  {
+    base::RunLoop loop;
+    base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
+                                                  loop.QuitClosure());
+    loop.Run();
+  }
+
+  std::string focused_element;
+
+  // Attempt to change focus in the inert subframe. This should fail.
+  // The setTimeout ensures that the inert bit can propagate before the
+  // test JS code runs.
+  EXPECT_TRUE(ExecuteScriptAndExtractString(
+      iframe_node,
+      "window.setTimeout(() => {text2.focus();"
+      "domAutomationController.send(document.activeElement.id);}, 0)",
+      &focused_element));
+  EXPECT_EQ("", focused_element);

[alexmos, 2017/06/16 02:17:57]

I was also curious about scenarios like the page dynamically adding a subframe
while its top frame is showing a modal dialog, and then navigating the subframe
cross-site (and maybe remote-to-local after that).  I *think* those should work
correctly (e.g., the swaps should preserve the bit), but just wanted to see if
you've thought about them.  Don't know if it's worth adding test coverage for
that, as it's unlikely to happen in practice, but might be worth it if it's
easy.

[kenrb, 2017/06/19 19:26:22]

The bit needs to be sent again after a swap from one process to another, which I
have added to the next PS. Also, I have added a navigation to this test in order
to verify the bit is preserved.

+}
+
 }  // namespace content