Fix images drawn with the NineImagePainter class in high DPI.

ui/gfx/skia_util.cc

 // 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 "ui/gfx/skia_util.h"
 
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
 #include "third_party/skia/include/core/SkUnPreMultiply.h"
@@ skipping 46 matching lines @@
   flattened->set(4, SkMScalarToScalar(transform.matrix().get(1, 1)));
   flattened->set(5, SkMScalarToScalar(transform.matrix().get(1, 3)));
   flattened->set(6, SkMScalarToScalar(transform.matrix().get(3, 0)));
   flattened->set(7, SkMScalarToScalar(transform.matrix().get(3, 1)));
   flattened->set(8, SkMScalarToScalar(transform.matrix().get(3, 3)));
 }
 
 skia::RefPtr<SkShader> CreateImageRepShader(const gfx::ImageSkiaRep& image_rep,
                                             SkShader::TileMode tile_mode,
                                             const SkMatrix& local_matrix) {
+  return CreateImageRepShaderForScale(image_rep, tile_mode, local_matrix,
+                                      image_rep.scale());
+}
+
+skia::RefPtr<SkShader> CreateImageRepShaderForScale(
+    const gfx::ImageSkiaRep& image_rep,
+    SkShader::TileMode tile_mode,
+    const SkMatrix& local_matrix,
+    SkScalar scale) {
   skia::RefPtr<SkShader> shader = skia::AdoptRef(SkShader::CreateBitmapShader(
       image_rep.sk_bitmap(), tile_mode, tile_mode));
   SkScalar scale_x = local_matrix.getScaleX();
   SkScalar scale_y = local_matrix.getScaleY();
-  SkScalar bitmap_scale = SkFloatToScalar(image_rep.scale());
 
-  // Unscale matrix by |bitmap_scale| such that the bitmap is drawn at the
+  // Unscale matrix by |scale| such that the bitmap is drawn at the
   // correct density.
   // Convert skew and translation to pixel coordinates.
   // Thus, for |bitmap_scale| = 2:
   //   x scale = 2, x translation = 1 DIP,
   // should be converted to
   //   x scale = 1, x translation = 2 pixels.
   SkMatrix shader_scale = local_matrix;
-  shader_scale.preScale(bitmap_scale, bitmap_scale);
-  shader_scale.setScaleX(SkScalarDiv(scale_x, bitmap_scale));
-  shader_scale.setScaleY(SkScalarDiv(scale_y, bitmap_scale));
+  shader_scale.preScale(scale, scale);
+  shader_scale.setScaleX(SkScalarDiv(scale_x, scale));
+  shader_scale.setScaleY(SkScalarDiv(scale_y, scale));
 
   shader->setLocalMatrix(shader_scale);
   return shader;
 }
 
 skia::RefPtr<SkShader> CreateGradientShader(int start_point,
                                             int end_point,
                                             SkColor start_color,
                                             SkColor end_color) {
   SkColor grad_colors[2] = { start_color, end_color};
@@ skipping 80 matching lines @@
     } else {
       rgba[i + 0] = SkGetPackedR32(pixel_in);
       rgba[i + 1] = SkGetPackedG32(pixel_in);
       rgba[i + 2] = SkGetPackedB32(pixel_in);
       rgba[i + 3] = alpha;
     }
   }
 }
 
 }  // namespace gfx