Always set NSTexturedBackgroundWindowMask 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/mac_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/cocoa/browser_window_utils.h"
 #import "chrome/browser/ui/cocoa/chrome_event_processing_window.h"
+#import "chrome/browser/ui/cocoa/custom_frame_view.h"
 #include "chrome/browser/ui/cocoa/extensions/extension_keybinding_registry_cocoa.h"
 #include "chrome/browser/ui/cocoa/extensions/extension_view_mac.h"
 #import "chrome/browser/ui/cocoa/nsview_additions.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/common/extension.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/gfx/skia_util.h"
@@ skipping 192 matching lines @@
 @end
 
 // TODO(jamescook): Should these be AppNSWindow to match apps::AppWindow?
 // http://crbug.com/344082
 @interface ShellNSWindow : ChromeEventProcessingWindow
 @end
 @implementation ShellNSWindow
 @end
 
 @interface ShellCustomFrameNSWindow : ShellNSWindow
-
-- (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view;
-
 @end
 
 @implementation ShellCustomFrameNSWindow
 
 - (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view {
   [[NSBezierPath bezierPathWithRect:rect] addClip];
   [[NSColor clearColor] set];
   NSRectFill(rect);
 
   // Set up our clip.
   CGFloat cornerRadius = 4.0;
   if ([view respondsToSelector:@selector(roundedCornerRadius)])
     cornerRadius = [view roundedCornerRadius];
   [[NSBezierPath bezierPathWithRoundedRect:[view bounds]
                                    xRadius:cornerRadius
                                    yRadius:cornerRadius] addClip];
   [[NSColor whiteColor] set];
   NSRectFill(rect);
 }
 
 @end
 
-@interface ShellFramelessNSWindow : ShellCustomFrameNSWindow
-
+@interface ShellFramelessNSWindow : ShellNSWindow
 @end
 
 @implementation ShellFramelessNSWindow
 
+- (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view {}
+
 + (NSRect)frameRectForContentRect:(NSRect)contentRect
                         styleMask:(NSUInteger)mask {
   return contentRect;
 }
 
 + (NSRect)contentRectForFrameRect:(NSRect)frameRect
                         styleMask:(NSUInteger)mask {
   return frameRect;
 }
 
@@ skipping 99 matching lines @@
 
   extension_keybinding_registry_.reset(new ExtensionKeybindingRegistryCocoa(
       Profile::FromBrowserContext(app_window_->browser_context()),
       window,
       extensions::ExtensionKeybindingRegistry::PLATFORM_APPS_ONLY,
       NULL));
 }
 
 NSUInteger NativeAppWindowCocoa::GetWindowStyleMask() const {
   NSUInteger style_mask = NSTitledWindowMask | NSClosableWindowMask |
-                          NSMiniaturizableWindowMask;
+                          NSMiniaturizableWindowMask |
+                          NSTexturedBackgroundWindowMask;
   if (shows_resize_controls_)
     style_mask |= NSResizableWindowMask;
-  if (!has_frame_ ||
-      !CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kAppsUseNativeFrame)) {
-    style_mask |= NSTexturedBackgroundWindowMask;
-  }
   return style_mask;
 }
 
 void NativeAppWindowCocoa::InstallView() {
   NSView* view = WebContents()->GetNativeView();
   if (has_frame_) {
     [view setFrame:[[window() contentView] bounds]];
     [[window() contentView] addSubview:view];
     if (!shows_fullscreen_controls_)
       [[window() standardWindowButton:NSWindowZoomButton] setEnabled:NO];
@@ skipping 558 matching lines @@
 }
 
 void NativeAppWindowCocoa::UpdateRestoredBounds() {
   if (IsRestored(*this))
     restored_bounds_ = [window() frame];
 }
 
 void NativeAppWindowCocoa::HideWithoutMarkingHidden() {
   [window() orderOut:window_controller_];
 }