mac: Tweak minimum tab width to match bitmap assets

chrome/browser/ui/cocoa/tabs/tab_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_controller.h"
 
 #include <cmath>
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
@@ skipping 45 matching lines @@
     [target_ commandDispatch:command forController:owner_];
   }
 
  private:
   id<TabControllerTarget> target_;  // weak
   TabController* owner_;  // weak, owns me
 };
 
 }  // TabControllerInternal namespace
 
-// The min widths match the windows values and are sums of left + right
-// padding, of which we have no comparable constants (we draw using paths, not
-// images). The selected tab width includes the close button width.
-+ (CGFloat)minTabWidth { return 31; }
-+ (CGFloat)minSelectedTabWidth { return 46; }
+// The min widths is the smallest number at which the right edge of the right
+// tab border image is not visibly clipped.  It is a bit smaller than the sum
+// of the two tab edge bitmaps because these bitmaps have a few transparent
+// pixels on the side.  The selected tab width includes the close button width.
++ (CGFloat)minTabWidth { return 35; }
++ (CGFloat)minSelectedTabWidth { return 52; }
 + (CGFloat)maxTabWidth { return 214; }
 + (CGFloat)miniTabWidth { return 58; }
 + (CGFloat)appTabWidth { return 66; }
 
 - (TabView*)tabView {
   DCHECK([[self view] isKindOfClass:[TabView class]]);
   return static_cast<TabView*>([self view]);
 }
 
 - (id)init {
@@ skipping 302 matching lines @@
 // TabStripDragController.
 - (BOOL)tabCanBeDragged:(TabController*)controller {
   return [[target_ dragController] tabCanBeDragged:controller];
 }
 
 - (void)maybeStartDrag:(NSEvent*)event forTab:(TabController*)tab {
   [[target_ dragController] maybeStartDrag:event forTab:tab];
 }
 
 @end