Converts Widget::SetOpacity from char to float

chrome/browser/ui/views/download/download_started_animation_views.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/download/download_started_animation.h"
 
 #include "base/macros.h"
 #include "content/public/browser/web_contents.h"
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 95 matching lines @@
   popup_->Close();
 }
 
 void DownloadStartedAnimationViews::AnimateToState(double state) {
   if (state >= 1.0) {
     Close();
   } else {
     Reposition();
 
     // Start at zero, peak halfway and end at zero.
-    double opacity = std::min(1.0 - pow(GetCurrentValue() - 0.5, 2) * 4.0,
-                              static_cast<double>(1.0));
-
-    popup_->SetOpacity(static_cast<unsigned char>(opacity * 255.0));
+    popup_->SetOpacity(static_cast<float>(
+        std::min(1.0 - pow(GetCurrentValue() - 0.5, 2) * 4.0, 1.0)));
   }
 }
 
 }  // namespace
 
 // static
 void DownloadStartedAnimation::Show(content::WebContents* web_contents) {
   // The animation will delete itself when it's finished.
   new DownloadStartedAnimationViews(web_contents);
 }