Mac: Make image dragging 162.4% more awesome.

skia/ext/skia_utils_mac.mm

 // Copyright (c) 2006-2008 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 "skia/ext/skia_utils_mac.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/scoped_cftyperef.h"
@@ skipping 150 matching lines @@
           operation:NSCompositeCopy
            fraction:1.0];
 
   // Done drawing, restore context.
   [NSGraphicsContext restoreGraphicsState];
 
   return bitmap;
 }
 
 NSImage* SkBitmapToNSImage(const SkBitmap& skiaBitmap) {
+  if (skiaBitmap.isNull())
+    return nil;
+
   // First convert SkBitmap to CGImageRef.
   CGImageRef cgimage = SkCreateCGImageRef(skiaBitmap);
 
   // Now convert to NSImage.
   NSBitmapImageRep* bitmap = [[[NSBitmapImageRep alloc]
                                    initWithCGImage:cgimage] autorelease];
   CFRelease(cgimage);
   NSImage* image = [[[NSImage alloc] init] autorelease];
   [image addRepresentation:bitmap];
   [image setSize:NSMakeSize(skiaBitmap.width(), skiaBitmap.height())];
   return image;
 }
 
 SkBitmap AppplicationIconAtSize(int size) {
   NSImage* image = [NSImage imageNamed:@"NSApplicationIcon"];
   return NSImageToSkBitmap(image, NSMakeSize(size, size), /* is_opaque=*/true);
 }
 
 }  // namespace gfx