base::RefCounted now DCHECKs when referenced from multiple threads.

ui/gfx/image/image.cc

Index: ui/gfx/image/image.cc
diff --git a/ui/gfx/image/image.cc b/ui/gfx/image/image.cc
index 170c51465df3f38fa92ab1299a6aeac7845fcf14..8606730c8f23830ce5b4800e105734f9356748fc 100644
--- a/ui/gfx/image/image.cc
+++ b/ui/gfx/image/image.cc
@@ -338,7 +338,8 @@ class ImageRepCocoa : public ImageRep {
 // The Storage class acts similarly to the pixels in a SkBitmap: the Image
 // class holds a refptr instance of Storage, which in turn holds all the
 // ImageReps. This way, the Image can be cheaply copied.
-class ImageStorage : public base::RefCounted<ImageStorage> {
+// TODO(mgiuca): Avoid using UnsafeRefCounted. http://crbug.com/469952.
+class ImageStorage : public base::UnsafeRefCounted<ImageStorage> {
  public:
   ImageStorage(Image::RepresentationType default_type)
       : default_representation_type_(default_type),
@@ -364,7 +365,7 @@ class ImageStorage : public base::RefCounted<ImageStorage> {
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 
  private:
-  friend class base::RefCounted<ImageStorage>;
+  friend class base::UnsafeRefCounted<ImageStorage>;
 
   ~ImageStorage() {}