[ios] Improve toolbar in tab_grid

ios/clean/chrome/browser/ui/tab_grid/tab_grid_collection_view_layout.mm

 // Copyright 2017 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 "ios/clean/chrome/browser/ui/tab_grid/tab_grid_collection_view_layout.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace {
 const CGFloat kMinTabWidth = 200.0f;
 const CGFloat kMaxTabWidth = 250.0f;
 const CGFloat kInterTabSpacing = 20.0f;
-const UIEdgeInsets kSectionInset = {20.0f, 20.0f, 20.0f, 20.0f};
+const UIEdgeInsets kSectionInset = {10.0f, 20.0f, 20.0f, 20.0f};

[marq (ping after 24h), 2017/03/02 06:04:54]

Nit: Prefer not to use static struct assignment to UIKit types where constructor
functions exist.

[edchin, 2017/03/02 07:12:43]

Will do.

[edchin, 2017/03/16 07:19:59]

Done.

 }
 
 @implementation TabGridCollectionViewLayout
 
 #pragma mark - UICollectionViewLayout
 
 // This is called whenever the layout is invalidated, including during rotation.
 - (void)prepareLayout {
   [super prepareLayout];
   [self updateLayoutWithBounds:[[self collectionView] bounds].size];
@@ skipping 11 matching lines @@
     columns++;
     tabWidth = (boundsSize.width - kInterTabSpacing * (columns + 1)) / columns;
   }
   self.itemSize = CGSizeMake(tabWidth, tabWidth);
   self.sectionInset = kSectionInset;
   self.minimumLineSpacing = kInterTabSpacing;
   self.minimumInteritemSpacing = kInterTabSpacing;
 }
 
 @end