Order the GL overlays above windows if possible.

content/browser/web_contents/web_contents_view_mac.mm

 // 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.
 
 #import <Carbon/Carbon.h>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 61 matching lines @@
     WebContentsViewDelegate* delegate,
     RenderViewHostDelegateView** render_view_host_delegate_view) {
   WebContentsViewMac* rv = new WebContentsViewMac(web_contents, delegate);
   *render_view_host_delegate_view = rv;
   return rv;
 }
 
 WebContentsViewMac::WebContentsViewMac(WebContentsImpl* web_contents,
                                        WebContentsViewDelegate* delegate)
     : web_contents_(web_contents),
-      delegate_(delegate) {
+      delegate_(delegate),
+      allow_overlapping_views_(false) {
 }
 
 WebContentsViewMac::~WebContentsViewMac() {
   // This handles the case where a renderer close call was deferred
   // while the user was operating a UI control which resulted in a
   // close.  In that case, the Cocoa view outlives the
   // WebContentsViewMac instance due to Cocoa retain count.
   [cocoa_view_ cancelDeferredClose];
   [cocoa_view_ clearWebContentsView];
 }
@@ skipping 16 matching lines @@
     return render_widget_host->GetView();
   }
 
   RenderWidgetHostViewMac* view = static_cast<RenderWidgetHostViewMac*>(
       RenderWidgetHostView::CreateViewForWidget(render_widget_host));
   if (delegate()) {
     NSObject<RenderWidgetHostViewMacDelegate>* rw_delegate =
         delegate()->CreateRenderWidgetHostViewDelegate(render_widget_host);
     view->SetDelegate(rw_delegate);
   }
+  view->SetAllowOverlappingViews(allow_overlapping_views_);
 
   // Fancy layout comes later; for now just make it our size and resize it
   // with us. In case there are other siblings of the content area, we want
   // to make sure the content area is on the bottom so other things draw over
   // it.
   NSView* view_view = view->GetNativeView();
   [view_view setFrame:[cocoa_view_.get() bounds]];
   [view_view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
   // Add the new view below all other views; this also keeps it below any
   // overlay view installed.
@@ skipping 198 matching lines @@
                     withObject:nil
                     afterDelay:0.0];
 }
 
 gfx::Rect WebContentsViewMac::GetViewBounds() const {
   // This method is not currently used on mac.
   NOTIMPLEMENTED();
   return gfx::Rect();
 }
 
+void WebContentsViewMac::SetAllowOverlappingViews(bool overlapping) {
+  if (allow_overlapping_views_ == overlapping)
+    return;
+
+  allow_overlapping_views_ = overlapping;
+  RenderWidgetHostViewMac* view = static_cast<RenderWidgetHostViewMac*>(
+      web_contents_->GetRenderWidgetHostView());
+  if (view)
+    view->SetAllowOverlappingViews(allow_overlapping_views_);
+}
+
 void WebContentsViewMac::CloseTab() {
   web_contents_->Close(web_contents_->GetRenderViewHost());
 }
 
 }  // namespace content
 
 @implementation WebContentsViewCocoa
 
 - (id)initWithWebContentsViewMac:(WebContentsViewMac*)w {
   self = [super initWithFrame:NSZeroRect];
@@ skipping 189 matching lines @@
       [[[notification userInfo] objectForKey:kSelectionDirection]
         unsignedIntegerValue];
   if (direction == NSDirectSelection)
     return;
 
   [self webContents]->
       FocusThroughTabTraversal(direction == NSSelectingPrevious);
 }
 
 @end