patch from issue 2577273002 at patchset 20001 (http://crrev.com/2577273002#ps20001)

chrome/browser/icon_manager.h

Index: chrome/browser/icon_manager.h
diff --git a/chrome/browser/icon_manager.h b/chrome/browser/icon_manager.h
index 43c36acedc0e64f6e91e00f4e7c84878081fe16a..503a7ed7d47201573a9cb8f35f6bb094e996568b 100644
--- a/chrome/browser/icon_manager.h
+++ b/chrome/browser/icon_manager.h
@@ -54,10 +54,10 @@
 #include "chrome/browser/icon_loader.h"
 #include "ui/gfx/image/image.h"
 
-class IconManager : public IconLoader::Delegate {
+class IconManager {
  public:
   IconManager();
-  ~IconManager() override;
+  ~IconManager();
 
   // Synchronous call to examine the internal caches for the icon. Returns the
   // icon if we have already loaded it, or null if we don't have it and must
@@ -67,7 +67,7 @@ class IconManager : public IconLoader::Delegate {
   gfx::Image* LookupIconFromFilepath(const base::FilePath& file_path,
                                      IconLoader::IconSize size);
 
-  using IconRequestCallback = base::Callback<void(gfx::Image*)>;
+  using IconRequestCallback = base::OnceCallback<void(gfx::Image*)>;
 
   // Asynchronous call to lookup and return the icon associated with file. The
   // work is done on the file thread, with the callbacks running on the thread
@@ -82,14 +82,13 @@ class IconManager : public IconLoader::Delegate {
   base::CancelableTaskTracker::TaskId LoadIcon(
       const base::FilePath& file_name,
       IconLoader::IconSize size,
-      const IconRequestCallback& callback,
+      IconRequestCallback callback,
       base::CancelableTaskTracker* tracker);
 
  private:
-  // IconLoader::Delegate interface.
-  void OnImageLoaded(IconLoader* loader,
-                     std::unique_ptr<gfx::Image> result,
-                     const IconLoader::IconGroup& group) override;
+  void OnIconLoaded(IconLoader* loader,
+                    std::unique_ptr<gfx::Image> result,
+                    const IconLoader::IconGroup& group);
 
   struct CacheKey {
     CacheKey(const IconLoader::IconGroup& group, IconLoader::IconSize size);