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

chrome/browser/ui/views/panels/panel_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/panels/panel_view.h"
 
 #include <map>
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 20 matching lines @@
 #include "base/win/windows_version.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/browser/ui/views/panels/taskbar_window_thumbnailer_win.h"
 #include "ui/base/win/shell.h"
 #include "ui/gfx/icon_util.h"
 #include "ui/views/win/hwnd_util.h"
 #endif
 
 namespace {
 
+#if defined(OS_WIN)
 // If the height of a stacked panel shrinks below this threshold during the
 // user resizing, it will be treated as minimized.
 const int kStackedPanelHeightShrinkThresholdToBecomeMinimized =
     panel::kTitlebarHeight + 20;
+#endif
 
 // Supported accelerators.
 // Note: We can't use the acclerator table defined in chrome/browser/ui/views
 // due to checkdeps violation.
 struct AcceleratorMapping {
   ui::KeyboardCode keycode;
   int modifiers;
   int command_id;
 };
 const AcceleratorMapping kPanelAcceleratorMap[] = {
@@ skipping 1092 matching lines @@
   DCHECK(thickness_for_mouse_resizing > 0);
   SkRegion* region = new SkRegion;
   region->op(0, 0, thickness_for_mouse_resizing, height, SkRegion::kUnion_Op);
   region->op(width - thickness_for_mouse_resizing, 0, width, height,
       SkRegion::kUnion_Op);
   region->op(0, height - thickness_for_mouse_resizing, width, height,
       SkRegion::kUnion_Op);
   web_contents->GetRenderViewHost()->GetView()->SetClickthroughRegion(region);
 #endif
 }