Always add 100P scale format in the supported format list.

ui/gfx/image/image_ios.mm

 // Copyright 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 "ui/gfx/image/image.h"
 
 #import <UIKit/UIKit.h>
 
 #include "base/logging.h"
 #include "base/memory/scoped_nsobject.h"
 #include "ui/base/layout.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_skia_util_ios.h"
 
 namespace gfx {
 namespace internal {
 
 void PNGFromUIImage(UIImage* uiimage, std::vector<unsigned char>* png) {
   NSData* data = UIImagePNGRepresentation(uiimage);
 
   if ([data length] == 0)
     return;
 
   png->resize([data length]);
   [data getBytes:&png->at(0) length:[data length]];
 }
 
 UIImage* CreateUIImageFromPNG(const std::vector<unsigned char>& png) {
-  // iOS only supports one scale factor.
-  std::vector<ui::ScaleFactor> supported_scale_factors =
-      ui::GetSupportedScaleFactors();
-  DCHECK_EQ(1U, supported_scale_factors.size());
-  if (supported_scale_factors.size() < 1)
-    return nil;
-
-  ui::ScaleFactor scale_factor = supported_scale_factors[0];
+  ui::ScaleFactor scale_factor = ui::GetMaxScaleFactor();
   float scale = ui::GetScaleFactorScale(scale_factor);
 
   NSData* data = [NSData dataWithBytes:&png.front() length:png.size()];
   scoped_nsobject<UIImage> image (
       [[UIImage alloc] initWithData:data scale:scale]);
   if (!image) {
     LOG(WARNING) << "Unable to decode PNG into UIImage.";
     // Return a 16x16 red image to visually show error.
     BOOL opaque = YES;
     UIGraphicsBeginImageContextWithOptions(CGSizeMake(16, 16), opaque, scale);
@@ skipping 28 matching lines @@
     bitmap.allocPixels();
     bitmap.eraseRGB(0xff, 0, 0);
     return new ImageSkia(bitmap);
   }
 
   return new ImageSkia(ImageSkiaFromUIImage(uiimage));
 }
 
 } // namespace internal
 } // namespace gfx