Implement window.alert() and its cousins for extensions.

Second try, now with fixed observer.

BUG=12126
TEST=put a window.prompt() in a background page, a browser action, and a page action.
Make sure it gets the result back correctly. Also make sure it still works when
called from a web page.
Review URL: http://codereview.chromium.org/373006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31204 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 6 deletions

diff --git a/chrome/browser/views/jsmessage_box_dialog.cc b/chrome/browser/views/jsmessage_box_dialog.cc
index 3fb70e0..b83242f 100644
--- a/chrome/browser/views/jsmessage_box_dialog.cc
+++ b/chrome/browser/views/jsmessage_box_dialog.cc
@@ -37,10 +37,15 @@ JavascriptMessageBoxDialog::~JavascriptMessageBoxDialog() {
 }
 
 void JavascriptMessageBoxDialog::ShowModalDialog() {
-  HWND root_hwnd = GetAncestor(tab_contents()->GetNativeView(),
-                               GA_ROOT);
-  dialog_ = views::Window::CreateChromeWindow(root_hwnd, gfx::Rect(), this);
-  dialog_->Show();
+  gfx::NativeWindow root_hwnd = client()->GetMessageBoxRootWindow();
+  // GetMessageBoxRootWindow() will be NULL if there's no selected tab (e.g.,
+  // during shutdown), in which case we simply skip showing this dialog.
+  if (!root_hwnd) {
+    Cancel();
+  } else {
+    dialog_ = views::Window::CreateChromeWindow(root_hwnd, gfx::Rect(), this);
+    dialog_->Show();
+  }
 }
 
 void JavascriptMessageBoxDialog::ActivateModalDialog() {
@@ -72,13 +77,12 @@ int JavascriptMessageBoxDialog::GetDialogButtons() const {
 }
 
 std::wstring JavascriptMessageBoxDialog::GetWindowTitle() const {
-  return parent_->title();;
+  return parent_->title();
 }
 
 
 void JavascriptMessageBoxDialog::WindowClosing() {
   dialog_ = NULL;
-
 }
 
 void JavascriptMessageBoxDialog::DeleteDelegate() {