Converts Widget::SetOpacity from char to float

ui/views/widget/desktop_aura/desktop_window_tree_host.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_H_
 
 #include <memory>
 
 #include "ui/aura/window_event_dispatcher.h"
@@ skipping 119 matching lines @@
   // Determines whether the window should use native title bar and borders.
   virtual bool ShouldUseNativeFrame() const = 0;
   // Determines whether the window contents should be rendered transparently
   // (for example, so that they can overhang onto the window title bar).
   virtual bool ShouldWindowContentsBeTransparent() const = 0;
   virtual void FrameTypeChanged() = 0;
 
   virtual void SetFullscreen(bool fullscreen) = 0;
   virtual bool IsFullscreen() const = 0;
 
-  virtual void SetOpacity(unsigned char opacity) = 0;
+  virtual void SetOpacity(float opacity) = 0;
 
   virtual void SetWindowIcons(const gfx::ImageSkia& window_icon,
                               const gfx::ImageSkia& app_icon) = 0;
 
   virtual void InitModalType(ui::ModalType modal_type) = 0;
 
   virtual void FlashFrame(bool flash_frame) = 0;
 
   virtual void OnRootViewLayout() = 0;
 
   // Called when the DesktopNativeWidgetAura's aura::Window is focused and
   // blurred.
   virtual void OnNativeWidgetFocus() = 0;
   virtual void OnNativeWidgetBlur() = 0;
 
   // Returns true if the Widget was closed but is still showing because of
   // animations.
   virtual bool IsAnimatingClosed() const = 0;
 
   // Returns true if the Widget supports translucency.
   virtual bool IsTranslucentWindowOpacitySupported() const = 0;
 
   // Called when the window's size constraints change.
   virtual void SizeConstraintsChanged() = 0;
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_H_