Compute the correct height above the tabstrip when dragging tabs.

chrome/browser/ui/views/tabs/tab_drag_controller.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/tab_drag_controller.h"
 
 #include <math.h>
 #include <set>
 
 #include "base/auto_reset.h"
@@ skipping 1669 matching lines @@
       views::View::ConvertPointToWidget(source, &right_edge);
       new_bounds.set_x(point_in_screen.x() - right_edge.x());
       new_bounds.Offset(drag_bounds->back().right() - mouse_offset_.x(), 0);
       OffsetX(-(*drag_bounds)[0].x(), drag_bounds);
       break;
     }
     default:
       break; // Nothing to do for DETACH_ABOVE_OR_BELOW.
   }
 
-  // To account for the extra vertical on restored windows that is absent on
-  // maximized windows, add an additional vertical offset extracted from the tab
-  // strip.
-  if (source->GetWidget()->IsMaximized())
-    new_bounds.Offset(0, -source->kNewTabButtonVerticalOffset);
+  // Account for the extra space above the tabstrip on restored windows versus
+  // maximized windows.
+  if (source->GetWidget()->IsMaximized()) {
+    const auto* frame_view = static_cast<BrowserNonClientFrameView*>(
+        source->GetWidget()->non_client_view()->frame_view());
+    new_bounds.Offset(
+        0, frame_view->GetTopInset(false) - frame_view->GetTopInset(true));
+  }
   return new_bounds;
 }
 
 void TabDragController::AdjustBrowserAndTabBoundsForDrag(
     int last_tabstrip_width,
     const gfx::Point& point_in_screen,
     std::vector<gfx::Rect>* drag_bounds) {
   attached_tabstrip_->InvalidateLayout();
   attached_tabstrip_->DoLayout();
   const int dragged_tabstrip_width = attached_tabstrip_->GetTabAreaWidth();
@@ skipping 104 matching lines @@
       chrome::HOST_DESKTOP_TYPE_NATIVE);
   for (BrowserList::const_iterator it = browser_list->begin();
        it != browser_list->end(); ++it) {
     if ((*it)->tab_strip_model()->empty())
       exclude.insert((*it)->window()->GetNativeWindow());
   }
 #endif
   return GetLocalProcessWindowAtPoint(host_desktop_type_, screen_point, exclude,
                                       dragged_window);
 }