Remove all the OS X 10.6 SDK forward declarations.

chrome/browser/ui/panels/panel_window_controller_cocoa.mm

 // Copyright (c) 2012 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/panels/panel_window_controller_cocoa.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
@@ skipping 36 matching lines @@
 const int kMinimumWindowSize = 1;
 const double kBoundsAnimationSpeedPixelsPerSecond = 1000;
 const double kBoundsAnimationMaxDurationSeconds = 0.18;
 
 // Resize edge thickness, in screen pixels.
 const double kWidthOfMouseResizeArea = 4.0;
 // The distance the user has to move the mouse while keeping the left button
 // down before panel resizing operation actually starts.
 const double kDragThreshold = 3.0;
 
-// Replicate specific 10.6 SDK declarations for building with prior SDKs.
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
-
-enum {
-  NSWindowCollectionBehaviorParticipatesInCycle = 1 << 5
-};
-
-#endif  // MAC_OS_X_VERSION_10_6
-
 @interface PanelWindowControllerCocoa (PanelsCanBecomeKey)
 // Internal helper method for extracting the total number of panel windows
 // from the panel manager. Used to decide if panel can become the key window.
 - (int)numPanels;
 @end
 
 @implementation PanelWindowCocoaImpl
 // The panels cannot be reduced to 3-px windows on the edge of the screen
 // active area (above Dock). Default constraining logic makes at least a height
 // of the titlebar visible, so the user could still grab it. We do 'restore'
@@ skipping 968 matching lines @@
 - (NSRect)contentRectForFrameRect:(NSRect)frameRect {
   NSRect contentRect = [[[self window] contentView] convertRect:frameRect
                                                        fromView:nil];
   contentRect.size.height -= panel::kTitlebarHeight;
   if (contentRect.size.height < 0)
     contentRect.size.height = 0;
   return contentRect;
 }
 
 @end