Load the resources for max scale factor first.

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_path.h"
 #include "base/file_util.h"
 #include "base/memory/ref_counted_memory.h"
@@ skipping 317 matching lines @@
 
 // Test requesting image reps at various scale factors from the image returned
 // via ResourceBundle::GetImageNamed().
 TEST(ResourceBundle, GetImageNamed) {
   // On Windows, the default data is compiled into the binary so this does
   // nothing.
   ScopedTempDir dir;
   ASSERT_TRUE(dir.CreateUniqueTempDir());
 
   FilePath locale_path = dir.path().Append(FILE_PATH_LITERAL("empty.pak"));
-  FilePath data_path = dir.path().Append(FILE_PATH_LITERAL("sample.pak"));
+  FilePath data_default_path =
+      dir.path().Append(FILE_PATH_LITERAL("sample.pak"));
+  FilePath data_1x_path = dir.path().Append(FILE_PATH_LITERAL("sample_1x.pak"));
   FilePath data_2x_path = dir.path().Append(FILE_PATH_LITERAL("sample_2x.pak"));
 
   {
     // Create the pak files.
     ASSERT_EQ(file_util::WriteFile(locale_path, kEmptyPakContents,
         kEmptyPakSize), static_cast<int>(kEmptyPakSize));
-    CreateDataPackWithSingleBitmap(data_path, 10);
+    CreateDataPackWithSingleBitmap(data_default_path, 10);
+    CreateDataPackWithSingleBitmap(data_1x_path, 10);
     CreateDataPackWithSingleBitmap(data_2x_path, 20);
 
     // Load the regular and 2x pak files.
     ResourceBundle resource_bundle(NULL);
-    resource_bundle.LoadTestResources(data_path, locale_path);
+    resource_bundle.LoadTestResources(data_default_path, locale_path);
+    resource_bundle.AddDataPackFromPath(data_1x_path, SCALE_FACTOR_100P);
     resource_bundle.AddDataPackFromPath(data_2x_path, SCALE_FACTOR_200P);
 
     gfx::ImageSkia* image_skia = resource_bundle.GetImageSkiaNamed(3);
 
+    EXPECT_EQ(ui::GetMaxScaleFactor(),
+              image_skia->image_reps()[0].scale_factor());
+
     // Resource ID 3 exists in both 1x and 2x paks. Image reps should be
     // available for both scale factors in |image_skia|.
     gfx::ImageSkiaRep image_rep =
         image_skia->GetRepresentation(ui::SCALE_FACTOR_100P);
     EXPECT_EQ(ui::SCALE_FACTOR_100P, image_rep.scale_factor());
     image_rep = image_skia->GetRepresentation(ui::SCALE_FACTOR_200P);
     EXPECT_EQ(ui::SCALE_FACTOR_200P, image_rep.scale_factor());
 
     // The 1.4x pack was not loaded. Requesting the 1.4x resource should return
     // either the 1x or the 2x resource.
     image_rep = image_skia->GetRepresentation(ui::SCALE_FACTOR_140P);
     EXPECT_TRUE(image_rep.scale_factor() == ui::SCALE_FACTOR_100P ||
                 image_rep.scale_factor() == ui::SCALE_FACTOR_200P);
   }
 }
 
+TEST(ResourceBundle, FallbackToNone) {
+  // On Windows, the default data is compiled into the binary so this does
+  // nothing.
+  ScopedTempDir dir;
+  ASSERT_TRUE(dir.CreateUniqueTempDir());
+
+  FilePath locale_path = dir.path().Append(FILE_PATH_LITERAL("empty.pak"));

[sail, 2012/11/05 23:46:39]

use AppendASCII instead of FILE_PATH_LITERAL? same below

[oshima, 2012/11/06 00:36:51]

Done. changed all instance of this.

+  FilePath data_default_path =
+      dir.path().Append(FILE_PATH_LITERAL("sample.pak"));
+
+  {

[sail, 2012/11/05 23:46:39]

do you really need this?

[oshima, 2012/11/06 00:36:51]

removed here and above.

+    // Create the pak files.
+    ASSERT_EQ(file_util::WriteFile(locale_path, kEmptyPakContents,
+        kEmptyPakSize), static_cast<int>(kEmptyPakSize));
+    CreateDataPackWithSingleBitmap(data_default_path, 10);
+
+    // Load the regular and 2x pak files.

[sail, 2012/11/05 23:46:39]

I can't tell how this code loads both regular and 2x pak files

[oshima, 2012/11/06 00:36:51]

fixed the comment.

+    ResourceBundle resource_bundle(NULL);
+    resource_bundle.LoadTestResources(data_default_path, locale_path);
+
+    gfx::ImageSkia* image_skia = resource_bundle.GetImageSkiaNamed(3);
+    EXPECT_EQ(1ui, image_skia->image_reps().size());
+    EXPECT_EQ(ui::SCALE_FACTOR_100P,
+              image_skia->image_reps()[0].scale_factor());
+  }
+}
+
 }  // namespace ui