Switch to doing user-resizing via system for panels on Mac

chrome/browser/ui/panels/stacked_panel_collection.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/panels/stacked_panel_collection.h"
 
 #include <algorithm>
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 608 matching lines @@
 
 bool StackedPanelCollection::HasPanel(Panel* panel) const {
   return std::find(panels_.begin(), panels_.end(), panel) != panels_.end();
 }
 
 void StackedPanelCollection::UpdatePanelOnCollectionChange(Panel* panel) {
   panel->set_attention_mode(
       static_cast<Panel::AttentionMode>(Panel::USE_PANEL_ATTENTION |
                                         Panel::USE_SYSTEM_ATTENTION));
   panel->ShowShadow(false);
-  panel->EnableResizeByMouse(true);
   panel->UpdateMinimizeRestoreButtonVisibility();
   UpdatePanelCornerStyle(panel);
 }
 
 void StackedPanelCollection::OnPanelExpansionStateChanged(Panel* panel) {
   DCHECK_NE(Panel::MINIMIZED, panel->expansion_state());
 
   // Ensure minimized panel does not get the focus. If minimizing all,
   // the active panel will be deactivated once when all panels are minimized
   // rather than per minimized panel.
@@ skipping 144 matching lines @@
   if (available_space < 0)
     available_space = 0;
   return available_space;
 }
 
 NativePanelStackWindow* StackedPanelCollection::GetStackWindowForPanel(
     Panel* panel) const {
   return secondary_stack_window_ && secondary_stack_window_->HasPanel(panel) ?
       secondary_stack_window_ : primary_stack_window_;
 }