Extract locking behaviour from ProcessSingleton.

chrome/browser/first_run/try_chrome_dialog_view.cc

Index: chrome/browser/first_run/try_chrome_dialog_view.cc
diff --git a/chrome/browser/first_run/try_chrome_dialog_view.cc b/chrome/browser/first_run/try_chrome_dialog_view.cc
index 11042a71cb7439093d64d428e432f8e7595937d0..b176ac1ffacd05ab00de8e56829a7ebbbf91bbae 100644
--- a/chrome/browser/first_run/try_chrome_dialog_view.cc
+++ b/chrome/browser/first_run/try_chrome_dialog_view.cc
@@ -55,14 +55,14 @@ const int kRadioGroupID = 1;
 // static
 TryChromeDialogView::Result TryChromeDialogView::Show(
     size_t flavor,
-    ProcessSingleton* process_singleton) {
+    const ActiveModalDialogListener& listener) {
   if (flavor > 10000) {
     // This is a test value. We want to make sure we exercise
     // returning this early. See TryChromeDialogBrowserTest test.
     return NOT_NOW;
   }
   TryChromeDialogView dialog(flavor);
-  return dialog.ShowModal(process_singleton);
+  return dialog.ShowModal(listener);
 }
 
 TryChromeDialogView::TryChromeDialogView(size_t flavor)
@@ -79,7 +79,7 @@ TryChromeDialogView::~TryChromeDialogView() {
 }
 
 TryChromeDialogView::Result TryChromeDialogView::ShowModal(
-    ProcessSingleton* process_singleton) {
+    const ActiveModalDialogListener& listener) {
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
 
   views::ImageView* icon = new views::ImageView();
@@ -295,14 +295,13 @@ TryChromeDialogView::Result TryChromeDialogView::ShowModal(
 #endif
   SetToastRegion(toast_window, preferred.width(), preferred.height());
 
-  // Time to show the window in a modal loop. The ProcessSingleton should
-  // already be locked and it will not process WM_COPYDATA requests. Change the
-  // window to bring to foreground if a request arrives.
-  CHECK(process_singleton->locked());
-  process_singleton->SetForegroundWindow(popup_->GetNativeView());
+  // Time to show the window in a modal loop.
   popup_->Show();
+  if (!listener.is_null())
+    listener.Run(popup_->GetNativeView());
   MessageLoop::current()->Run();

[gab, 2013/03/27 18:03:26]

We shouldn't run the MessageLoop before the end of PreMainMessageLoopRun (and
this seems to be called before that... i.e., right after PreProfileInit()).

Would there be a way to CHECK if the MessageLoop is ever ran while the
process_singleton is locked? We could then fix all instances of this paradigm
and prevent further introductions of it.

[erikwright (departed), 2013/03/28 03:16:34]

I'm sure a way could be found to do that, but keep in mind that, at the moment,
that would be a bad thing to do because there is existing code that does run the
message loop before the end of PreMainMessageLoopRun.

Note that this is another advantage of the SequencedTaskRunner API. It doesn't
expose Run(), so by eliminating the global static MessageLoop::current() you
would prevent people from calling MessageLoop::Run when you don't want them to.

-  process_singleton->SetForegroundWindow(NULL);
+  if (!listener.is_null())
+    listener.Run(NULL);
   return result_;
 }