Bring the feedback button to the Mac sad tab

chrome/browser/ui/cocoa/tab_contents/sad_tab_mac.mm

+// Copyright (c) 2011 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.
+
+#import "chrome/browser/ui/cocoa/tab_contents/sad_tab_view_cocoa.h"
+#include "chrome/browser/ui/sad_tab.h"
+#include "content/public/browser/web_contents.h"
+
+namespace {
+
+class SadTabCocoa : public chrome::SadTab {
+ public:
+  SadTabCocoa(content::WebContents* web_contents, chrome::SadTabKind kind)
+      : SadTab(web_contents, kind) {
+    NSView* web_contents_view = web_contents->GetNativeView();
+    sad_tab_view_ =
+        [[SadTabView alloc] initWithFrame:web_contents_view.bounds sadTab:this];
+    [web_contents_view addSubview:sad_tab_view_];
+    [sad_tab_view_ release];
+  }
+
+  ~SadTabCocoa() override { [sad_tab_view_ removeFromSuperview]; }
+
+ private:
+  // Owned by web_contents
+  SadTabView* sad_tab_view_;
+};
+
+}  // namespace
+
+chrome::SadTab* chrome::SadTab::Create(content::WebContents* web_contents,
+                                       SadTabKind kind) {
+  return new SadTabCocoa(web_contents, kind);
+}