Use LANCZOS3 resize algorithm to generate missing image reps for extension action icons.

ui/gfx/image/image_skia_operations.h

Index: ui/gfx/image/image_skia_operations.h
diff --git a/ui/gfx/image/image_skia_operations.h b/ui/gfx/image/image_skia_operations.h
index 80326b6f2df1ef911eeae43e293c33b897deaec1..7e81b53c073b2804f70a07f5bda5d799b24eb53e 100644
--- a/ui/gfx/image/image_skia_operations.h
+++ b/ui/gfx/image/image_skia_operations.h
@@ -79,10 +79,20 @@ class UI_EXPORT ImageSkiaOperations {
                                  const gfx::Rect& subset_bounds);
 
   // Creates an image by resizing |source| to given |target_dip_size|.
+  // If |source| is missing the representation for a required scale factor, the
+  // representation for the scale factor will be generated by resizing one of
+  // |source|'s existing representations' bitmap to the target pixel size.

[pkotwicz, 2012/10/17 18:42:20]

Nit: mention that we are resizing using |methd| in this case.

[tbarzic, 2012/10/17 19:00:46]

Done.

   static ImageSkia CreateResizedImage(const ImageSkia& source,
                                       skia::ImageOperations::ResizeMethod methd,
                                       const Size& target_dip_size);
 
+  // Creates an image which inherits image representations from |source|.
+  // Image representations for the scale factors not containted in |source| are
+  // generated by resizing existing representations using |resize_method|.
+  static ImageSkia SetFallbackResizeMethod(

[pkotwicz, 2012/10/17 18:42:20]

How about GetImageWithCustomResizeMethod() ?

[tbarzic, 2012/10/17 19:00:46]

yeah, sounds much better (I'll use 'Create' instead of 'Get' to be consistent
with the rest of the names in the file)..

+      const ImageSkia& source,
+      skia::ImageOperations::ResizeMethod method);
+
   // Creates an image with drop shadow defined in |shadows| for |source|.
   static ImageSkia CreateImageWithDropShadow(const ImageSkia& source,
                                              const ShadowValues& shadows);