Update LayoutTestBrowserMain and BlinkTestController loop quit logic.

Migrate the LayoutTestBrowserMain and BlinkTestController classes to use
the quit closure registered with the content::Shell by the default main
message loop, to exit it, rather than QuitCurrent*Deprecated().

Bug: 844016
Change-Id: I0b7e8249df6ed62757e5bb27c51dd16b35e0e4a6
Reviewed-on: https://chromium-review.googlesource.com/1106814Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569063}

content/shell/browser/layout_test/blink_test_controller.cc

@@ -824,9 +824,8 @@ void BlinkTestController::DiscardMainWindow() {
   devtools_protocol_test_bindings_.reset();
   WebContentsObserver::Observe(nullptr);
   if (test_phase_ != BETWEEN_TESTS) {
+    // CloseAllWindows will also signal the main message loop to exit.
     Shell::CloseAllWindows();
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::RunLoop::QuitCurrentWhenIdleClosureDeprecated());
     test_phase_ = CLEAN_UP;
   } else if (main_window_) {
     main_window_->Close();
@@ -1192,14 +1191,14 @@ void BlinkTestController::OnResetDone() {
   }
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::RunLoop::QuitCurrentWhenIdleClosureDeprecated());
+      FROM_HERE, base::BindOnce(&Shell::QuitMainMessageLoopForTesting));
 }
 
 void BlinkTestController::OnLeakDetectionDone(
     const LeakDetector::LeakDetectionReport& report) {
   if (!report.leaked) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::RunLoop::QuitCurrentWhenIdleClosureDeprecated());
+        FROM_HERE, base::BindOnce(&Shell::QuitMainMessageLoopForTesting));
     return;
   }
 

content/shell/browser/layout_test/layout_test_browser_main.cc

@@ -98,8 +98,9 @@ int RunTests(const std::unique_ptr<content::BrowserMainRunner>& main_runner) {
     }
   }
   if (!ran_at_least_once) {
+    // CloseAllWindows will cause the |main_runner| loop to quit.
     base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::RunLoop::QuitCurrentWhenIdleClosureDeprecated());
+        FROM_HERE, base::BindOnce(&content::Shell::CloseAllWindows));
     main_runner->Run();
   }
 
@@ -149,9 +150,8 @@ int LayoutTestBrowserMain(
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kCheckLayoutTestSysDeps)) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::RunLoop::QuitCurrentWhenIdleClosureDeprecated());
+        FROM_HERE, base::BindOnce(&content::Shell::CloseAllWindows));
     main_runner->Run();
-    content::Shell::CloseAllWindows();
     main_runner->Shutdown();
     return 0;
   }

content/shell/browser/shell.cc

@@ -174,6 +174,11 @@ void Shell::CloseAllWindows() {
   // Pump the message loop to allow window teardown tasks to run.
   base::RunLoop().RunUntilIdle();
 
+  // If there were no windows open then the message loop quit closure will
+  // not have been run.
+  if (*g_quit_main_message_loop)
+    std::move(*g_quit_main_message_loop).Run();
+
   PlatformExit();
 }
 
@@ -181,6 +186,10 @@ void Shell::SetMainMessageLoopQuitClosure(base::OnceClosure quit_closure) {
   *g_quit_main_message_loop = std::move(quit_closure);
 }
 
+void Shell::QuitMainMessageLoopForTesting() {
+  std::move(*g_quit_main_message_loop).Run();
+}
+
 void Shell::SetShellCreatedCallback(
     base::Callback<void(Shell*)> shell_created_callback) {
   DCHECK(shell_created_callback_.is_null());

content/shell/browser/shell.h

@@ -113,13 +113,19 @@ class Shell : public WebContentsDelegate,
   // Returns the currently open windows.
   static std::vector<Shell*>& windows() { return windows_; }
 
-  // Closes all windows and returns.
+  // Closes all windows, pumps teardown tasks, then returns. The main message
+  // loop will be signalled to quit, before the call returns.
   static void CloseAllWindows();
 
   // Stores the supplied |quit_closure|, to be run when the last Shell instance
   // is destroyed.
   static void SetMainMessageLoopQuitClosure(base::OnceClosure quit_closure);
 
+  // Used by the BlinkTestController to stop the message loop before closing all
+  // windows, for specific tests. Fails if called after the message loop has
+  // already been signalled to quit.
+  static void QuitMainMessageLoopForTesting();
+
   // Used for content_browsertests. Called once.
   static void SetShellCreatedCallback(
       base::Callback<void(Shell*)> shell_created_callback);