Remove ImageLoadingTracker class

chrome/browser/extensions/extension_icon_manager_unittest.cc

Index: chrome/browser/extensions/extension_icon_manager_unittest.cc
diff --git a/chrome/browser/extensions/extension_icon_manager_unittest.cc b/chrome/browser/extensions/extension_icon_manager_unittest.cc
index 957d030e5faaaf7cf7d1f4bea8d09eac502db8d8..26495b2a76761b08e38856f90b9fb1f6bc204fd3 100644
--- a/chrome/browser/extensions/extension_icon_manager_unittest.cc
+++ b/chrome/browser/extensions/extension_icon_manager_unittest.cc
@@ -76,9 +76,8 @@ class TestIconManager : public ExtensionIconManager {
   explicit TestIconManager(ExtensionIconManagerTest* test) : test_(test) {}
   virtual ~TestIconManager() {}
 
-  // Implements the ImageLoadingTracker::Observer interface, and calls through
-  // to the base class' implementation. Then it lets the test know that an
-  // image load was observed.
+  // Overrides the ImageLoader callback, and calls through to the base class'
+  // implementation. Then it lets the test know that an image load was observed.
   virtual void OnImageLoaded(const std::string& extension_id,
                              const gfx::Image& image) OVERRIDE {
     ExtensionIconManager::OnImageLoaded(extension_id, image);