Make panels turn on or off shadow effect.

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.h"
 #include "base/utf_string_conversions.h"
@@ skipping 626 matching lines @@
 }
 
 void PanelView::MinimizePanelBySystem() {
   window_->Minimize();
 }
 
 bool PanelView::IsPanelMinimizedBySystem() const {
   return window_->IsMinimized();
 }
 
+void PanelView::ShowShadow(bool show) {
+#if defined(OS_WIN)
+  // The overlapped window has the shadow while the popup window does not have
+  // the shadow.
+  int overlap_style = WS_OVERLAPPED | WS_THICKFRAME | WS_SYSMENU;
+  int popup_style = WS_POPUP;
+  UpdateWindowAttribute(GWL_STYLE,
+                        show ? overlap_style : popup_style,
+                        show ? popup_style : overlap_style,
+                        true);
+#endif
+}
+
 void PanelView::AttachWebContents(content::WebContents* contents) {
   web_view_->SetWebContents(contents);
 }
 
 void PanelView::DetachWebContents(content::WebContents* contents) {
   web_view_->SetWebContents(NULL);
 }
 
 NativePanelTesting* PanelView::CreateNativePanelTesting() {
   return new NativePanelTestingWin(this);
@@ skipping 411 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
 }