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

chrome/browser/cocoa/constrained_window_mac.mm

Index: chrome/browser/cocoa/constrained_window_mac.mm
diff --git a/chrome/browser/cocoa/constrained_window_mac.mm b/chrome/browser/cocoa/constrained_window_mac.mm
new file mode 100644
index 0000000000000000000000000000000000000000..67d1030147fbc4f29a2b2dd888555a77581c832d
--- /dev/null
+++ b/chrome/browser/cocoa/constrained_window_mac.mm
@@ -0,0 +1,87 @@
+// 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/constrained_window_mac.h"
+
+#import "chrome/browser/cocoa/browser_window_controller.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/tab_contents/tab_contents_view.h"
+#import "third_party/GTM/AppKit/GTMWindowSheetController.h"
+
+ConstrainedWindowMacDelegate::~ConstrainedWindowMacDelegate() {}
+
+void ConstrainedWindowMacDelegateSystemSheet::RunSheet(
+    GTMWindowSheetController* sheetController,
+    NSView* view) {
+  NSArray* params = [NSArray arrayWithObjects:
+      [NSNull null],  // window, must be [NSNull null]
+      delegate_.get(),
+      [NSValue valueWithPointer:didEndSelector_],
+      [NSValue valueWithPointer:NULL],  // context info for didEndSelector_.
+      nil];
+  [sheetController beginSystemSheet:systemSheet_
+                       modalForView:view
+                     withParameters:params];
+}
+
+void ConstrainedWindowMacDelegateCustomSheet::RunSheet(
+    GTMWindowSheetController* sheetController,
+    NSView* view) {
+  [sheetController beginSheet:customSheet_.get()
+                 modalForView:view modalDelegate:delegate_.get()
+               didEndSelector:didEndSelector_
+                  contextInfo:NULL];
+}
+
+// static
+ConstrainedWindow* ConstrainedWindow::CreateConstrainedDialog(
+    TabContents* parent,
+    ConstrainedWindowMacDelegate* delegate) {
+  return new ConstrainedWindowMac(parent, delegate);
+}
+
+ConstrainedWindowMac::ConstrainedWindowMac(
+    TabContents* owner, ConstrainedWindowMacDelegate* delegate)
+    : owner_(owner),
+      delegate_(delegate),
+      controller_(nil) {
+  DCHECK(owner);
+  DCHECK(delegate);
+
+  // The TabContents only has a native window if it is currently visible. In
+  // this case, open the sheet now. Else, Realize() will be called later, when
+  // our tab becomes visible.
+  NSWindow* browserWindow = owner_->view()->GetTopLevelNativeWindow();
+  NSWindowController* controller = [browserWindow windowController];
+  if (controller != nil) {
+    DCHECK([controller isKindOfClass:[BrowserWindowController class]]);
+    Realize(static_cast<BrowserWindowController*>(controller));
+  }
+}
+
+ConstrainedWindowMac::~ConstrainedWindowMac() {}
+
+void ConstrainedWindowMac::CloseConstrainedWindow() {
+  // Note: controller_ can be `nil` here if the sheet was never realized. That's
+  // ok.
+  [controller_ removeConstrainedWindow:this];
+  delegate_->DeleteDelegate();
+  owner_->WillClose(this);
+
+  delete this;
+}
+
+void ConstrainedWindowMac::Realize(BrowserWindowController* controller) {
+  if (controller_ != nil) {
+    DCHECK(controller_ == controller);
+    return;
+  }
+  DCHECK(controller != nil);
+
+  // Remember the controller we're adding ourselves to, so that we can later
+  // remove us from it.
+  controller_ = controller;
+  [controller_ attachConstrainedWindow:this];
+  delegate_->set_sheet_open(true);
+}