Only show a beforeunload dialog if a frame has had a user gesture since its load.

content/browser/frame_host/render_frame_host_impl_browsertest.cc

Index: content/browser/frame_host/render_frame_host_impl_browsertest.cc
diff --git a/content/browser/frame_host/render_frame_host_impl_browsertest.cc b/content/browser/frame_host/render_frame_host_impl_browsertest.cc
index 5f467554e62c1979c685e02fcf56874736d739e0..4103d6a46d24acb69109bbef9f283e0daea3db7d 100644
--- a/content/browser/frame_host/render_frame_host_impl_browsertest.cc
+++ b/content/browser/frame_host/render_frame_host_impl_browsertest.cc
@@ -248,7 +248,11 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,
       "document.body.appendChild(iframe);"
       "iframe.contentWindow.onbeforeunload=function(e){return 'x'};";
   EXPECT_TRUE(content::ExecuteScript(wc, script));
-  EXPECT_TRUE(WaitForLoadStop(shell()->web_contents()));
+  EXPECT_TRUE(WaitForLoadStop(wc));
+
+  // JavaScript onbeforeunload dialogs require a user gesture.
+  for (auto* frame : wc->GetAllFrames())
+    frame->ExecuteJavaScriptWithUserGestureForTests(base::string16());
 
   // Force a process switch by going to a privileged page. The beforeunload
   // timer will be started on the top-level frame but will be paused while the
@@ -281,4 +285,37 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,
   wc->SetJavaScriptDialogManagerForTesting(nullptr);
 }
 
+// Tests that a gesture is required in a frame before it can request a
+// beforeunload dialog.
+IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,
+                       BeforeUnloadDialogRequiresGesture) {
+  WebContentsImpl* wc = static_cast<WebContentsImpl*>(shell()->web_contents());
+  TestJavaScriptDialogManager dialog_manager;
+  wc->SetDelegate(&dialog_manager);
+
+  EXPECT_TRUE(NavigateToURL(
+      shell(), GetTestUrl("render_frame_host", "beforeunload.html")));
+  // Disable the hang monitor, otherwise there will be a race between the
+  // beforeunload dialog and the beforeunload hang timer.
+  wc->GetMainFrame()->DisableBeforeUnloadHangMonitorForTesting();

[Nico, 2017/04/07 20:05:28]

Huh, I guess it makes sense here.

[Avi (use Gerrit), 2017/05/05 15:30:04]

Done.

+
+  // Reload. There should be no beforeunload dialog because there was no gesture
+  // on the page. If there was, this WaitForLoadStop call will hang.
+  wc->GetController().Reload(ReloadType::NORMAL, false);
+  EXPECT_TRUE(WaitForLoadStop(wc));
+
+  // Give the page a user gesture and try leaving again. This time there
+  // should be a dialog. If there is no dialog, the call to Wait will hang.
+  wc->GetMainFrame()->ExecuteJavaScriptWithUserGestureForTests(
+      base::string16());
+  shell()->LoadURL(GURL("about:blank"));
+  dialog_manager.Wait();
+
+  // Answer the dialog.
+  dialog_manager.callback().Run(false, base::string16());
+
+  wc->SetDelegate(nullptr);
+  wc->SetJavaScriptDialogManagerForTesting(nullptr);
+}
+
 }  // namespace content