linux and chromeos: Turn on -Wunused-const-variable.

chrome/browser/ui/views/tabs/dragged_tab_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 "chrome/browser/ui/views/tabs/dragged_tab_view.h"
 
 #include "base/stl_util.h"
 #include "chrome/browser/ui/views/tabs/native_view_photobooth.h"
 #include "third_party/skia/include/core/SkShader.h"
 #include "ui/gfx/canvas.h"
 #include "ui/views/widget/widget.h"
 
 #if defined(USE_AURA)
 #include "ui/views/widget/native_widget_aura.h"
 #elif defined(OS_WIN)
 #include "ui/gfx/win/dpi.h"
 #include "ui/views/widget/native_widget_win.h"
 #endif
 
 static const int kTransparentAlpha = 200;
-static const int kOpaqueAlpha = 255;
 static const int kDragFrameBorderSize = 2;
 static const int kTwiceDragFrameBorderSize = 2 * kDragFrameBorderSize;
 static const float kScalingFactor = 0.5;
 static const SkColor kDraggedTabBorderColor = SkColorSetRGB(103, 129, 162);
 
 ////////////////////////////////////////////////////////////////////////////////
 // DraggedTabView, public:
 
 DraggedTabView::DraggedTabView(const std::vector<views::View*>& renderers,
                                const std::vector<gfx::Rect>& renderer_bounds,
@@ skipping 151 matching lines @@
 }
 
 gfx::Size DraggedTabView::PreferredContainerSize() {
   gfx::Size ps = GetPreferredSize();
   return gfx::Size(ScaleValue(ps.width()), ScaleValue(ps.height()));
 }
 
 int DraggedTabView::ScaleValue(int value) {
   return static_cast<int>(value * kScalingFactor);
 }