Reduce FOR_EACH_OBSERVER usage in extensions

extensions/browser/app_window/app_window_geometry_cache.cc

 // Copyright 2014 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 "extensions/browser/app_window/app_window_geometry_cache.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 114 matching lines @@
       value->SetInteger("h", bounds.height());
       value->SetInteger("screen_bounds_x", screen_bounds.x());
       value->SetInteger("screen_bounds_y", screen_bounds.y());
       value->SetInteger("screen_bounds_w", screen_bounds.width());
       value->SetInteger("screen_bounds_h", screen_bounds.height());
       value->SetInteger("state", it->second.window_state);
       value->SetString(
           "ts", base::Int64ToString(it->second.last_change.ToInternalValue()));
       dict->SetWithoutPathExpansion(it->first, std::move(value));
 
-      FOR_EACH_OBSERVER(
-          Observer,
-          observers_,
-          OnGeometryCacheChanged(extension_id, it->first, bounds));
+      for (auto& observer : observers_)
+        observer.OnGeometryCacheChanged(extension_id, it->first, bounds);
     }
 
     prefs_->SetGeometryCache(extension_id, std::move(dict));
   }
 }
 
 bool AppWindowGeometryCache::GetGeometry(const std::string& extension_id,
                                          const std::string& window_id,
                                          gfx::Rect* bounds,
                                          gfx::Rect* screen_bounds,
@@ skipping 153 matching lines @@
 
 void AppWindowGeometryCache::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void AppWindowGeometryCache::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 }  // namespace extensions