mac: Remove code that was only needed on 10.5

content/browser/renderer_host/backing_store_mac.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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "content/browser/renderer_host/backing_store_mac.h"
 
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
@@ skipping 162 matching lines @@
   // scroll. Thus, we only have to worry about pixels which will end up inside
   // the clipping rectangle. (Note that the clipping rectangle is not
   // translated by the scroll.)
 
   // We assume |clip_rect| is contained within the backing store.
   DCHECK(clip_rect.bottom() <= size().height());
   DCHECK(clip_rect.right() <= size().width());
 
   if ((dx || dy) && abs(dx) < size().width() && abs(dy) < size().height()) {
     if (cg_layer()) {
-      // Whether this version of OS X has broken CGLayers. See
-      // http://crbug.com/45553 , comments 5 and 6.
-      bool needs_layer_workaround = base::mac::IsOSLeopardOrEarlier();
-
-      base::mac::ScopedCFTypeRef<CGLayerRef> new_layer;
-      CGContextRef layer;
-
-      if (needs_layer_workaround) {
-        new_layer.reset(CreateCGLayer());
-        // If the current view is in a window, the replacement must be too.
-        DCHECK(new_layer);
-
-        layer = CGLayerGetContext(new_layer);
-        CGContextDrawLayerAtPoint(layer, CGPointMake(0, 0), cg_layer());
-      } else {
-        layer = CGLayerGetContext(cg_layer());
-      }
-
+      CGContextRef layer = CGLayerGetContext(cg_layer());
       CGContextSaveGState(layer);
       CGContextClipToRect(layer,
                           CGRectMake(clip_rect.x(),
                                      size().height() - clip_rect.bottom(),
                                      clip_rect.width(),
                                      clip_rect.height()));
       CGContextDrawLayerAtPoint(layer, CGPointMake(dx, -dy), cg_layer());
       CGContextRestoreGState(layer);
-
-      if (needs_layer_workaround)
-        cg_layer_.swap(new_layer);
     } else {
       // We don't have a layer, so scroll the contents of the CGBitmapContext.
       base::mac::ScopedCFTypeRef<CGImageRef> bitmap_image(
           CGBitmapContextCreateImage(cg_bitmap_));
       CGContextSaveGState(cg_bitmap_);
       CGContextClipToRect(cg_bitmap_,
                           CGRectMake(clip_rect.x(),
                                      size().height() - clip_rect.bottom(),
                                      clip_rect.width(),
                                      clip_rect.height()));
@@ skipping 54 matching lines @@
                                                pixel_size.width(),
                                                pixel_size.height(),
                                                8, pixel_size.width() * 4,
                                                base::mac::GetSystemColorSpace(),
                                                kCGImageAlphaPremultipliedFirst |
                                                    kCGBitmapByteOrder32Host);
   DCHECK(context);
 
   return context;
 }