Mac: Fix for janky tab dragging/reordering.

chrome/browser/ui/cocoa/tabs/tab_view.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 "chrome/browser/ui/cocoa/tabs/tab_view.h"
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 118 matching lines @@
   return YES;
 }
 
 - (void)mouseEntered:(NSEvent*)theEvent {
   isMouseInside_ = YES;
   [self resetLastGlowUpdateTime];
   [self adjustGlowValue];
 }
 
 - (void)mouseMoved:(NSEvent*)theEvent {
-  hoverPoint_ = [self convertPoint:[theEvent locationInWindow]
-                          fromView:nil];
-  [self setNeedsDisplay:YES];
+  if (state_ == NSOffState) {
+    hoverPoint_ = [self convertPoint:[theEvent locationInWindow] fromView:nil];
+    [self setNeedsDisplay:YES];
+  }
 }
 
 - (void)mouseExited:(NSEvent*)theEvent {
   isMouseInside_ = NO;
   hoverHoldEndTime_ =
       [NSDate timeIntervalSinceReferenceDate] + kHoverHoldDuration;
   [self resetLastGlowUpdateTime];
   [self adjustGlowValue];
 }
 
@@ skipping 634 matching lines @@
   CGFloat middleWidth = tabWidth - leftWidth - rightWidth;
   NSRect middleRect = NSMakeRect(leftWidth, 0, middleWidth, kFillHeight);
   [[NSColor whiteColor] setFill];
   NSRectFill(middleRect);
 
   maskCache_.reset(CGBitmapContextCreateImage(maskContext));
   return maskCache_;
 }
 
 @end  // @implementation TabView(Private)