Fix sizing when auto-scaling a missing resource at a non-integer scale factor.

ui/base/resource/resource_bundle_unittest.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/base/resource/resource_bundle.h"
 
 #include "base/base_paths.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 480 matching lines @@
 
   // The image rep for 2x should be available. It should be resized to the
   // proper 2x size.
   gfx::ImageSkiaRep image_rep =
     image_skia->GetRepresentation(ui::SCALE_FACTOR_200P);
   EXPECT_EQ(ui::SCALE_FACTOR_200P, image_rep.scale_factor());
   EXPECT_EQ(20, image_rep.pixel_width());
   EXPECT_EQ(20, image_rep.pixel_height());
 }
 
+#if defined(OS_WIN)
+// Tests GetImageNamed() behaves properly when the size of a scaled image
+// requires rounding as a result of using a non-integer scale factor.
+// Scale factors of 140 and 1805 are Windows specific.
+TEST_F(ResourceBundleImageTest, GetImageNamedFallback1xRounding) {
+  base::FilePath data_path = dir_path().AppendASCII("sample.pak");
+  base::FilePath data_140P_path = dir_path().AppendASCII("sample_140P.pak");
+  base::FilePath data_180P_path = dir_path().AppendASCII("sample_180P.pak");
+
+  CreateDataPackWithSingleBitmap(data_path, 8, base::StringPiece());
+  // Mark 140% and 180% images as requiring 1x fallback.
+  CreateDataPackWithSingleBitmap(data_140P_path, 8, base::StringPiece(
+    reinterpret_cast<const char*>(kPngScaleChunk),
+    arraysize(kPngScaleChunk)));
+  CreateDataPackWithSingleBitmap(data_180P_path, 8, base::StringPiece(
+    reinterpret_cast<const char*>(kPngScaleChunk),
+    arraysize(kPngScaleChunk)));
+
+  ResourceBundle* resource_bundle = CreateResourceBundleWithEmptyLocalePak();
+  resource_bundle->AddDataPackFromPath(data_path, SCALE_FACTOR_100P);
+  resource_bundle->AddDataPackFromPath(data_140P_path, SCALE_FACTOR_140P);
+  resource_bundle->AddDataPackFromPath(data_180P_path, SCALE_FACTOR_180P);
+
+  // Non-integer dimensions should be rounded up.
+  gfx::ImageSkia* image_skia = resource_bundle->GetImageSkiaNamed(3);
+  gfx::ImageSkiaRep image_rep =
+    image_skia->GetRepresentation(ui::SCALE_FACTOR_140P);
+  EXPECT_EQ(12, image_rep.pixel_width());
+  image_rep = image_skia->GetRepresentation(ui::SCALE_FACTOR_180P);
+  EXPECT_EQ(15, image_rep.pixel_width());
+}
+#endif
+
 TEST_F(ResourceBundleImageTest, FallbackToNone) {
   base::FilePath data_default_path = dir_path().AppendASCII("sample.pak");
 
   // Create the pak files.
   CreateDataPackWithSingleBitmap(data_default_path, 10, base::StringPiece());
 
     // Load the regular pak files only.
   ResourceBundle* resource_bundle = CreateResourceBundleWithEmptyLocalePak();
   resource_bundle->AddDataPackFromPath(data_default_path, SCALE_FACTOR_NONE);
 
   gfx::ImageSkia* image_skia = resource_bundle->GetImageSkiaNamed(3);
   EXPECT_EQ(1u, image_skia->image_reps().size());
   EXPECT_EQ(ui::SCALE_FACTOR_100P,
             image_skia->image_reps()[0].scale_factor());
 }
 
 }  // namespace ui