mac: Fix tab strip outline when dragging out a tab.

chrome/browser/ui/cocoa/tabs/tab_strip_controller.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_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 499 matching lines @@
   for (TabController* controller in closingControllers_.get()) {
     NSView* view = [controller view];
     [[[view animationForKey:@"frameOrigin"] delegate] invalidate];
   }
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   [tabStripView_ removeAllToolTips];
   [super dealloc];
 }
 
 + (CGFloat)defaultTabHeight {
-  return 25.0;
+  return 26.0;
 }
 
 + (CGFloat)defaultLeftIndentForControls {
   // Default indentation leaves enough room so tabs don't overlap with the
   // window controls.
   return 70.0;
 }
 
 // Finds the TabContentsController associated with the given index into the tab
 // model and swaps out the sole child of the contentArea to display its
@@ skipping 432 matching lines @@
   // them to correspond with the new tab positions.
   [tabStripView_ removeAllToolTips];
 
   for (TabController* tab in tabArray_.get()) {
     // Ignore a tab that is going through a close animation.
     if ([closingControllers_ containsObject:tab])
       continue;
 
     BOOL isPlaceholder = [[tab view] isEqual:placeholderTab_];
     NSRect tabFrame = [[tab view] frame];
-    tabFrame.size.height = [[self class] defaultTabHeight] + 1;
+    tabFrame.size.height = [[self class] defaultTabHeight];
     tabFrame.origin.y = 0;
     tabFrame.origin.x = offset;
 
     // If the tab is hidden, we consider it a new tab. We make it visible
     // and animate it in.
     BOOL newTab = [[tab view] isHidden];
     if (newTab)
       [[tab view] setHidden:NO];
 
     if (isPlaceholder) {
@@ skipping 1152 matching lines @@
 NSView* GetSheetParentViewForWebContents(WebContents* web_contents) {
   // View hierarchy of the contents view:
   // NSView  -- switchView, same for all tabs
   // +- NSView  -- TabContentsController's view
   //    +- TabContentsViewCocoa
   //
   // Changing it? Do not forget to modify
   // -[TabStripController swapInTabAtIndex:] too.
   return [web_contents->GetNativeView() superview];
 }