Run unload handlers when navigating to about:blank using PlzNavigate.

chrome/browser/ui/browser_browsertest.cc

Index: chrome/browser/ui/browser_browsertest.cc
diff --git a/chrome/browser/ui/browser_browsertest.cc b/chrome/browser/ui/browser_browsertest.cc
index 1226efd341b089e4af173fb084508771496ff653..c90e60dfe756161d7bd061625ee199eb2bd65bde 100644
--- a/chrome/browser/ui/browser_browsertest.cc
+++ b/chrome/browser/ui/browser_browsertest.cc
@@ -83,6 +83,7 @@
 #include "content/public/browser/interstitial_page.h"
 #include "content/public/browser/interstitial_page_delegate.h"
 #include "content/public/browser/navigation_entry.h"
+#include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/reload_type.h"
 #include "content/public/browser/render_frame_host.h"
@@ -94,6 +95,7 @@
 #include "content/public/browser/ssl_status.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/frame_navigate_params.h"
 #include "content/public/common/renderer_preferences.h"
 #include "content/public/common/url_constants.h"
@@ -332,6 +334,24 @@ class RenderViewSizeObserver : public content::WebContentsObserver {
   DISALLOW_COPY_AND_ASSIGN(RenderViewSizeObserver);
 };
 
+// Waits for a failed commit notification.
+class FailedCommitWatcher : public content::WebContentsObserver {
+public:
+  explicit FailedCommitWatcher(content::WebContents* wc)
+      : content::WebContentsObserver(wc) {}
+  void Wait() {
+    run_loop_.Run();
+  }
+
+ private:
+  void DidFinishNavigation(
+      content::NavigationHandle* navigation_handle) override {
+    CHECK(!navigation_handle->HasCommitted());
+    run_loop_.Quit();
+  }
+  base::RunLoop run_loop_;
+};
+
 }  // namespace
 
 class BrowserTest : public ExtensionBrowserTest {
@@ -672,7 +692,12 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, ReloadThenCancelBeforeUnload) {
   // the throbber stops spinning.
   chrome::Reload(browser(), WindowOpenDisposition::CURRENT_TAB);
   AppModalDialog* alert = ui_test_utils::WaitForAppModalDialog();
+
+  FailedCommitWatcher watcher(
+      browser()->tab_strip_model()->GetActiveWebContents());
   alert->CloseModalDialog();
+  if (content::IsBrowserSideNavigationEnabled())
+    watcher.Wait();
   EXPECT_FALSE(
       browser()->tab_strip_model()->GetActiveWebContents()->IsLoading());
 
@@ -824,7 +849,11 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, CancelBeforeUnloadResetsURL) {
 
   // Cancel the dialog.
   AppModalDialog* alert = ui_test_utils::WaitForAppModalDialog();
+  FailedCommitWatcher watcher(
+      browser()->tab_strip_model()->GetActiveWebContents());
   alert->CloseModalDialog();
+  if (content::IsBrowserSideNavigationEnabled())
+    watcher.Wait();
   EXPECT_FALSE(
       browser()->tab_strip_model()->GetActiveWebContents()->IsLoading());
 
@@ -893,8 +922,14 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, MAYBE_BeforeUnloadVsBeforeReload) {
   AppModalDialog* alert = ui_test_utils::WaitForAppModalDialog();
   EXPECT_TRUE(static_cast<JavaScriptAppModalDialog*>(alert)->is_reload());
 
-  // Cancel the reload.
+  // Cancel the reload. Wait for the ack from the renderer because the OpenURL
+  // call below tries to put up an unload dialog synchronously in the

[Charlie Reis, 2016/09/30 17:36:10]

nit: a beforeunload dialog

Also, I'm curious about the "synchronously" part.  Doesn't the dialog come from
the renderer (asynchronously)?

[jam, 2016/09/30 22:42:07]

I don't actually remember why I wrote it that way. I've removed the comment for
now. When PlzNavigate is the default the if statement would be gone.

+  // PlzNavigate case.
+  FailedCommitWatcher watcher(
+      browser()->tab_strip_model()->GetActiveWebContents());
   alert->native_dialog()->CancelAppModalDialog();
+  if (content::IsBrowserSideNavigationEnabled())
+    watcher.Wait();
 
   // Navigate to another url, and check that we get a "before unload" dialog.
   GURL url2(url::kAboutBlankURL);