[Extensions Toolbar] Add a finch config for the redesign

chrome/browser/extensions/extension_action.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/extension_action.h"
 
 #include <algorithm>
 
 #include "base/base64.h"
 #include "base/logging.h"
@@ skipping 238 matching lines @@
   }
   return default_icon_image_.get();
 }
 
 gfx::Image ExtensionAction::GetDefaultIconImage() const {
   // If we have a default icon, it should be loaded before trying to use it.
   DCHECK(!default_icon_image_ == !default_icon_);
   if (default_icon_image_)
     return default_icon_image_->image();
 
-  // If the extension action redesign is enabled, we use a special placeholder
-  // icon (with the first letter of the extension name) rather than the default
-  // (puzzle piece).
-  if (extensions::FeatureSwitch::extension_action_redesign()->IsEnabled()) {
-    return extensions::ExtensionIconPlaceholder::CreateImage(
-        extension_misc::EXTENSION_ICON_ACTION, extension_name_);
+  if (placeholder_icon_image_.IsEmpty()) {
+    // If the extension action redesign is enabled, we use a special placeholder
+    // icon (with the first letter of the extension name) rather than the
+    // default (puzzle piece).
+    if (extensions::FeatureSwitch::extension_action_redesign()->IsEnabled()) {
+      placeholder_icon_image_ =
+          extensions::ExtensionIconPlaceholder::CreateImage(
+              extension_misc::EXTENSION_ICON_ACTION, extension_name_);
+    } else {
+      placeholder_icon_image_ = GetDefaultIcon();
+    }
   }
 
-  return GetDefaultIcon();
+  return placeholder_icon_image_;
 }
 
 bool ExtensionAction::HasPopupUrl(int tab_id) const {
   return HasValue(popup_url_, tab_id);
 }
 
 bool ExtensionAction::HasTitle(int tab_id) const {
   return HasValue(title_, tab_id);
 }
 
@@ skipping 71 matching lines @@
   // If there is a default icon, the icon width will be set depending on our
   // action type.
   if (default_icon_)
     return GetIconSizeForType(action_type());
 
   // If no icon has been set and there is no default icon, we need favicon
   // width.
   return ui::ResourceBundle::GetSharedInstance().GetImageNamed(
           IDR_EXTENSIONS_FAVICON).Width();
 }