MacViews: Implement Tab Dragging

ui/views/cocoa/views_nswindow_delegate.mm

 // Copyright 2014 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 "ui/views/cocoa/views_nswindow_delegate.h"
 
 #include "base/logging.h"
 #import "ui/views/cocoa/bridged_content_view.h"
 #import "ui/views/cocoa/bridged_native_widget.h"
 #include "ui/views/widget/native_widget_mac.h"
@@ skipping 61 matching lines @@
   // windowDidExitFullScreen:. Also, failing to exit fullscreen just dumps the
   // window out of fullscreen without an animation; still sending the expected,
   // windowDidExitFullScreen: notification. So, again, nothing to do here.
   DCHECK(!parent_->target_fullscreen_state());
 }
 
 - (void)windowDidResize:(NSNotification*)notification {
   parent_->OnSizeChanged();
 }
 
+- (void)windowDidMove:(NSNotification*)notification {
+  // Note: windowDidMove: is sent only once at the end of a window drag. There
+  // is also windowWillMove: sent at the start, also once. Live updates are
+  // provided by BridgedNativeWidget only during RunMoveLoop().
+  parent_->OnPositionChanged();
+}
+
 - (void)windowDidBecomeKey:(NSNotification*)notification {
   parent_->OnWindowKeyStatusChangedTo(true);
 }
 
 - (void)windowDidResignKey:(NSNotification*)notification {
   parent_->OnWindowKeyStatusChangedTo(false);
 }
 
 - (void)windowWillClose:(NSNotification*)notification {
   DCHECK([parent_->ns_window() isEqual:[notification object]]);
@@ skipping 44 matching lines @@
             usingRect:(NSRect)defaultSheetLocation {
   // As per NSWindowDelegate documentation, the origin indicates the top left
   // point of the host frame in window coordinates. The width changes the
   // animation from vertical to trapezoid if it is smaller than the width of the
   // dialog. The height is ignored but should be set to zero.
   return NSMakeRect(0, [self nativeWidgetMac]->SheetPositionY(),
                     NSWidth(defaultSheetLocation), 0);
 }
 
 @end