Fixed all unused-variable Clang warnings on Windows.

ui/views/window/custom_frame_view.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 "ui/views/window/custom_frame_view.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/strings/utf_string_conversions.h"
@@ skipping 30 matching lines @@
 // In the window corners, the resize areas don't actually expand bigger, but the
 // 16 px at the end of each edge triggers diagonal resizing.
 const int kResizeAreaCornerSize = 16;
 // The titlebar never shrinks too short to show the caption button plus some
 // padding below it.
 const int kCaptionButtonHeightWithPadding = 19;
 // The titlebar has a 2 px 3D edge along the top and bottom.
 const int kTitlebarTopAndBottomEdgeThickness = 2;
 // The icon is inset 2 px from the left frame border.
 const int kIconLeftSpacing = 2;
-// The icon never shrinks below 16 px on a side.
-const int kIconMinimumSize = 16;
 // The space between the window icon and the title text.
 const int kTitleIconOffsetX = 4;
 // The space between the title text and the caption buttons.
 const int kTitleCaptionSpacing = 5;
 
+#if !defined(OS_WIN)
+// The icon never shrinks below 16 px on a side.
+const int kIconMinimumSize = 16;
+#endif
+
 #if defined(OS_CHROMEOS)
 // Chrome OS uses a dark gray.
 const SkColor kDefaultColorFrame = SkColorSetRGB(109, 109, 109);
 const SkColor kDefaultColorFrameInactive = SkColorSetRGB(176, 176, 176);
 #else
 // Windows and Linux use a blue.
 const SkColor kDefaultColorFrame = SkColorSetRGB(66, 116, 201);
 const SkColor kDefaultColorFrameInactive = SkColorSetRGB(161, 182, 228);
 #endif
 
@@ skipping 556 matching lines @@
     }
     case views::FRAME_BUTTON_CLOSE: {
       button = close_button_;
       break;
     }
   }
   return button;
 }
 
 }  // namespace views