Add support for constrained windows on os x, based on Avi's GTMWindowSheetController.

chrome/browser/cocoa/download_request_dialog_delegate_mac.mm

Index: chrome/browser/cocoa/download_request_dialog_delegate_mac.mm
diff --git a/chrome/browser/cocoa/download_request_dialog_delegate_mac.mm b/chrome/browser/cocoa/download_request_dialog_delegate_mac.mm
new file mode 100644
index 0000000000000000000000000000000000000000..3a34940932cfa7ffc2000e6e3f5cedf6233fc4f8
--- /dev/null
+++ b/chrome/browser/cocoa/download_request_dialog_delegate_mac.mm
@@ -0,0 +1,105 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/cocoa/download_request_dialog_delegate_mac.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "app/l10n_util_mac.h"
+#include "app/message_box_flags.h"
+#include "base/sys_string_conversions.h"
+#include "chrome/browser/tab_contents/constrained_window.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "grit/generated_resources.h"
+#include "views/controls/message_box_view.h"
+
+@interface SheetCallback : NSObject {
+  DownloadRequestDialogDelegateMac* target_;  // weak
+}
+- (id)initWithTarget:(DownloadRequestDialogDelegateMac*)target;
+- (void) alertDidEnd:(NSAlert *)alert
+          returnCode:(int)returnCode
+         contextInfo:(void *)contextInfo;
+@end
+
+@implementation SheetCallback
+- (id)initWithTarget:(DownloadRequestDialogDelegateMac*)target {
+  if ((self = [super init]) != nil) {
+    target_ = target;
+  }
+  return self;
+}
+- (void) alertDidEnd:(NSAlert *)alert
+          returnCode:(int)returnCode
+         contextInfo:(void *)contextInfo {
+  target_->SheetDidEnd(returnCode);
+}
+@end
+
+
+// static
+DownloadRequestDialogDelegate* DownloadRequestDialogDelegate::Create(
+    TabContents* tab,
+    DownloadRequestManager::TabDownloadState* host) {
+  return new DownloadRequestDialogDelegateMac(tab, host);
+}
+
+DownloadRequestDialogDelegateMac::DownloadRequestDialogDelegateMac(
+    TabContents* tab,
+    DownloadRequestManager::TabDownloadState* host)
+    : DownloadRequestDialogDelegate(host),
+      ConstrainedWindowMacDelegateSystemSheet(
+          [[[SheetCallback alloc] initWithTarget:this] autorelease],
+          @selector(alertDidEnd:returnCode:contextInfo:)),
+      responded_(false) {
+
+  // Set up alert.
+  NSAlert* alert = [[[NSAlert alloc] init] autorelease];
+  [alert addButtonWithTitle:
+      l10n_util::GetNSStringWithFixup(IDS_MULTI_DOWNLOAD_WARNING_ALLOW)];
+  NSButton* denyButton = [alert addButtonWithTitle:
+      l10n_util::GetNSStringWithFixup(IDS_MULTI_DOWNLOAD_WARNING_DENY)];
+  [alert setMessageText:
+      l10n_util::GetNSStringWithFixup(IDS_MULTI_DOWNLOAD_WARNING)];
+  [alert setAlertStyle:NSInformationalAlertStyle];
+
+  // Cocoa automatically gives ESC as a key equivalent to buttons with the text
+  // "Cancel". Since we use a different text, we have to set this ourselves.
+  NSString* escapeKey = @"\e";
+  [denyButton setKeyEquivalent:escapeKey];
+
+  set_sheet(alert);
+
+  // Display alert in a per-tab sheet.
+  window_ = tab->CreateConstrainedDialog(this);
+}
+
+void DownloadRequestDialogDelegateMac::CloseWindow() {
+  window_->CloseConstrainedWindow();
+}
+
+void DownloadRequestDialogDelegateMac::DeleteDelegate() {
+  if (is_sheet_open()) {
+    // Close sheet if it's still open.
+    [NSApp endSheet:[(NSAlert*)sheet() window]];  // class SheetDidEnd().
+    DCHECK(responded_);
+  }
+  if (!responded_) {
+    // Happens if the sheet was never visible
+    responded_ = true;
+    DoCancel();
+  }
+  DCHECK(!host_);
+  delete this;
+}
+
+void DownloadRequestDialogDelegateMac::SheetDidEnd(int returnCode) {
+  DCHECK(!responded_);
+  if (returnCode == NSAlertFirstButtonReturn) {
+    DoAccept();
+  } else {
+    DoCancel();
+  }
+  responded_ = true;
+}