[ios] Snapshot for WebState

ui/gfx/image/image_unittest_util_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.
 
 #import <CoreGraphics/CoreGraphics.h>
 #import <UIKit/UIKit.h>
 
 #include "base/mac/scoped_cftyperef.h"
 #include "skia/ext/skia_utils_ios.h"
 #include "ui/gfx/image/image_unittest_util.h"
 
 namespace gfx {
 namespace test {
 
 SkColor GetPlatformImageColor(PlatformImage image, int x, int y) {
   // Start by extracting the target pixel into a 1x1 CGImage.
-  base::ScopedCFTypeRef<CGImageRef> pixel_image(
-      CGImageCreateWithImageInRect(image.CGImage, CGRectMake(x, y, 1, 1)));
+
+  base::ScopedCFTypeRef<CGImageRef> pixel_image(CGImageCreateWithImageInRect(
+      image.CGImage, CGRectMake(x * image.scale, y * image.scale, 1, 1)));

[edchin, 2017/06/23 19:03:10]

I will pull this out into a separate CL and comment it
so it can be advertised appropriately. 

 
   // Draw that pixel into a 1x1 bitmap context.
   base::ScopedCFTypeRef<CGColorSpaceRef> color_space(
       CGColorSpaceCreateDeviceRGB());
   base::ScopedCFTypeRef<CGContextRef> bitmap_context(CGBitmapContextCreate(
       /*data=*/ NULL,
       /*width=*/ 1,
       /*height=*/ 1,
       /*bitsPerComponent=*/ 8,
       /*bytesPerRow=*/ 4,
       color_space,
       kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));
   CGContextDrawImage(bitmap_context, CGRectMake(0, 0, 1, 1), pixel_image);
 
   // The CGBitmapContext has the same memory layout as SkColor, so we can just
   // read an SkColor straight out of the context.
   SkColor* data =
       reinterpret_cast<SkColor*>(CGBitmapContextGetData(bitmap_context));
   return *data;
 }
 
 }  // namespace test
 }  // namespace gfx