Enable AutoResize for Constrained Web Dialogs for Mac.

chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.mm

Index: chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.mm
diff --git a/chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.mm b/chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.mm
index f043fad5a0c019634695a187d725aec839d59d58..60f3eff703678a98464cf276b56bab93dcba2b93 100644
--- a/chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.mm
+++ b/chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.mm
@@ -9,16 +9,37 @@
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_sheet.h"
 #import "chrome/browser/ui/cocoa/single_web_contents_dialog_manager_cocoa.h"
 #include "components/guest_view/browser/guest_view_base.h"
-#include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "content/public/browser/browser_thread.h"
 
 using web_modal::WebContentsModalDialogManager;
 
+ConstrainedWindowMac* ShowWebModalDialogMac(
+    ConstrainedWindowMacDelegate* delegate,
+    content::WebContents* web_contents,
+    id<ConstrainedWindowSheet> sheet) {
+  ConstrainedWindowMac* window = new ConstrainedWindowMac(delegate);
+  window->ShowDialog(web_contents, sheet);
+  return window;
+}
+
+ConstrainedWindowMac* CreateWebModalDialogMac(
+    ConstrainedWindowMacDelegate* delegate,
+    content::WebContents* web_contents,
+    id<ConstrainedWindowSheet> sheet) {
+  return new ConstrainedWindowMac(delegate, web_contents, sheet);
+}
+
+ConstrainedWindowMac::ConstrainedWindowMac(
+    ConstrainedWindowMacDelegate* delegate)
+    : delegate_(delegate) {
+}
+
 ConstrainedWindowMac::ConstrainedWindowMac(
     ConstrainedWindowMacDelegate* delegate,
     content::WebContents* web_contents,
     id<ConstrainedWindowSheet> sheet)
-    : delegate_(delegate) {
+    : delegate_(delegate),
+      sheet_(sheet) {
   DCHECK(sheet);
 
   // |web_contents| may be embedded within a chain of nested GuestViews. If it
@@ -26,15 +47,34 @@ ConstrainedWindowMac::ConstrainedWindowMac(
   web_contents =
       guest_view::GuestViewBase::GetTopLevelWebContents(web_contents);
 
+  dialog_manager_ =
+      WebContentsModalDialogManager::FromWebContents(web_contents);
+  native_manager_.reset(
+      new SingleWebContentsDialogManagerCocoa(this, sheet_, dialog_manager_));
+}
+
+ConstrainedWindowMac::~ConstrainedWindowMac() {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  native_manager_.reset();
+  DCHECK(!manager_);
+}
+
+void ConstrainedWindowMac::ShowDialog(
+    content::WebContents* web_contents,
+    id<ConstrainedWindowSheet> sheet) {
+  DCHECK(sheet);
+  web_contents =
+      guest_view::GuestViewBase::GetTopLevelWebContents(web_contents);
+
   auto manager = WebContentsModalDialogManager::FromWebContents(web_contents);
   scoped_ptr<SingleWebContentsDialogManagerCocoa> native_manager(
       new SingleWebContentsDialogManagerCocoa(this, sheet, manager));
   manager->ShowDialogWithManager([sheet sheetWindow], native_manager.Pass());
 }
 
-ConstrainedWindowMac::~ConstrainedWindowMac() {
-  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  DCHECK(!manager_);
+void ConstrainedWindowMac::ShowDialog() {
+  dialog_manager_->ShowDialogWithManager(
+      [sheet_ sheetWindow], native_manager_.Pass());
 }
 
 void ConstrainedWindowMac::CloseWebContentsModalDialog() {