Exit HeadlessBrowserImpl main message loop by QuitClosure.

Replace use of QuitCurrent*Deprecated() with use of the QuitClosure of
the //content default main message loop's RunLoop.

Bug: 844016
Change-Id: I14eb18304de9c9ddaabc2860998d12733572e7f7
Reviewed-on: https://chromium-review.googlesource.com/1103787
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568103}

headless/lib/browser/headless_browser_impl.cc

@@ -115,8 +115,7 @@ void HeadlessBrowserImpl::Shutdown() {
     browser_contexts_.clear();
   }
 
-  BrowserMainThread()->PostTask(
-      FROM_HERE, base::RunLoop::QuitCurrentWhenIdleClosureDeprecated());
+  browser_main_parts_->QuitMainMessageLoop();
 }
 
 std::vector<HeadlessBrowserContext*>

headless/lib/browser/headless_browser_main_parts.cc

@@ -12,8 +12,7 @@
 namespace headless {
 
 HeadlessBrowserMainParts::HeadlessBrowserMainParts(HeadlessBrowserImpl* browser)
-    : browser_(browser)
-    , devtools_http_handler_started_(false) {}
+    : browser_(browser) {}
 
 HeadlessBrowserMainParts::~HeadlessBrowserMainParts() = default;
 
@@ -27,6 +26,11 @@ void HeadlessBrowserMainParts::PreMainMessageLoopRun() {
   browser_->PlatformInitialize();
 }
 
+void HeadlessBrowserMainParts::PreDefaultMainMessageLoopRun(
+    base::OnceClosure quit_closure) {
+  quit_main_message_loop_ = std::move(quit_closure);
+}
+
 void HeadlessBrowserMainParts::PostMainMessageLoopRun() {
   if (devtools_http_handler_started_) {
     StopLocalDevToolsHttpHandler();
@@ -34,4 +38,9 @@ void HeadlessBrowserMainParts::PostMainMessageLoopRun() {
   }
 }
 
+void HeadlessBrowserMainParts::QuitMainMessageLoop() {
+  if (quit_main_message_loop_)
+    std::move(quit_main_message_loop_).Run();
+}
+
 }  // namespace headless

headless/lib/browser/headless_browser_main_parts.h

@@ -22,15 +22,19 @@ class HeadlessBrowserMainParts : public content::BrowserMainParts {
 
   // content::BrowserMainParts implementation:
   void PreMainMessageLoopRun() override;
+  void PreDefaultMainMessageLoopRun(base::OnceClosure quit_closure) override;
   void PostMainMessageLoopRun() override;
 #if defined(OS_MACOSX)
   void PreMainMessageLoopStart() override;
 #endif
 
+  void QuitMainMessageLoop();
+
  private:
   HeadlessBrowserImpl* browser_;  // Not owned.
 
-  bool devtools_http_handler_started_;
+  bool devtools_http_handler_started_ = false;
+  base::OnceClosure quit_main_message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(HeadlessBrowserMainParts);
 };