[Mac] Don't show a title on app windows.

chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm

 // Copyright 2013 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/ui/cocoa/apps/native_app_window_cocoa.h"
 
 #include "apps/app_shim/extension_app_shim_handler_mac.h"
 #include "base/command_line.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/mac_util.h"
@@ skipping 28 matching lines @@
 //
 // Attempting maximize and restore functionality with non resizable windows
 // using the native zoom method did not work, even with
 // windowWillUseStandardFrame, as the window would not restore back to the
 // desired size.
 
 using apps::AppWindow;
 
 @interface NSWindow (NSPrivateApis)
 - (void)setBottomCornerRounded:(BOOL)rounded;
+- (BOOL)_isTitleHidden;
 @end
 
 // Replicate specific 10.7 SDK declarations for building with prior SDKs.
 #if !defined(MAC_OS_X_VERSION_10_7) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
 
 @interface NSWindow (LionSDKDeclarations)
 - (void)toggleFullScreen:(id)sender;
 @end
 
@@ skipping 157 matching lines @@
 // view passed into -[NSWindow drawCustomFrameRect:forView:].
 @interface NSView (PrivateMethods)
 - (CGFloat)roundedCornerRadius;
 @end
 
 // TODO(jamescook): Should these be AppNSWindow to match apps::AppWindow?
 // http://crbug.com/344082
 @interface ShellNSWindow : ChromeEventProcessingWindow
 @end
 @implementation ShellNSWindow
+
+// Similar to ChromeBrowserWindow, don't draw the title, but allow it to be seen
+// in menus, Expose, etc.
+- (BOOL)_isTitleHidden {
+  return YES;
+}
+
 @end
 
 @interface ShellCustomFrameNSWindow : ShellNSWindow {
  @private
   base::scoped_nsobject<NSColor> color_;
   base::scoped_nsobject<NSColor> inactiveColor_;
 }
 
 - (void)setColor:(NSColor*)color
     inactiveColor:(NSColor*)inactiveColor;
@@ skipping 733 matching lines @@
 }
 
 void NativeAppWindowCocoa::UpdateRestoredBounds() {
   if (IsRestored(*this))
     restored_bounds_ = [window() frame];
 }
 
 void NativeAppWindowCocoa::HideWithoutMarkingHidden() {
   [window() orderOut:window_controller_];
 }