Paint tab-loading throbbers into a ui::Layer.

chrome/browser/ui/views/tabs/tab_strip.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_strip.h"
 
 #include <algorithm>
 #include <iterator>
 #include <string>
 #include <vector>
@@ skipping 1202 matching lines @@
     if (previous_tab_bounds.right() - GetLayoutConstant(TABSTRIP_TAB_OVERLAP) !=
         tab_bounds.x()) {
       int x = previous_tab_bounds.right() - tab_bounds.x() -
           kStackedTabRightClip;
       clip->SetRect(x, 0, tab_bounds.width() - x, tab_bounds.height());
     }
   }
   return true;
 }
 
+bool TabStrip::CanPaintThrobberToLayer() const {
+  // Disable layer-painting of throbbers if dragging, if any tab animation is in
+  // progress, or if stacked tabs are enabled.
+  const bool dragging = drag_controller_ && drag_controller_->started_drag();
+  return !touch_layout_ && !dragging && !IsAnimating();
+}
+
 bool TabStrip::IsImmersiveStyle() const {
   return immersive_style_;
 }
 
 void TabStrip::UpdateTabAccessibilityState(const Tab* tab,
                                            ui::AXViewState* state) {
   state->count = tab_count();
   state->index = GetModelIndexOfTab(tab);
 }
 
@@ skipping 1455 matching lines @@
           ConvertPointToViewAndGetEventHandler(this, newtab_button_, point);
       if (view)
         return view;
     }
     Tab* tab = FindTabForEvent(point);
     if (tab)
       return ConvertPointToViewAndGetEventHandler(this, tab, point);
   }
   return this;
 }