Cleanup for temporary variables

ios/chrome/browser/ui/authentication/signin_promo_view.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/chrome/browser/ui/authentication/signin_promo_view.h"
 
 #include "base/logging.h"
 #import "ios/chrome/browser/ui/colors/MDCPalette+CrAdditions.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #include "ios/chrome/grit/ios_chromium_strings.h"
@@ skipping 87 matching lines @@
           @(kVerticalPadding + kButtonVerticalPadding),
     };
     NSDictionary* views = @{
       @"imageView" : _imageView,
       @"primaryButton" : _primaryButton,
       @"secondaryButton" : _secondaryButton,
       @"textLabel" : _textLabel,
     };
 
     // Constraints shared between modes.
-    NSString* formatString = @"V:|-kVerticalPaddingx2-[imageView]-"
-                              "kVerticalPadding-[textLabel]-"
-                              "kVerticalPaddingkButtonVerticalPadding-["
-                              "primaryButton(kButtonHeight)]";
+    NSString* sharedVerticalConstraints =
+        @"V:|-kVerticalPaddingx2-[imageView]-kVerticalPadding-[textLabel]-"
+        @"kVerticalPaddingkButtonVerticalPadding-[primaryButton(kButtonHeight)"
+        @"]";
     NSArray* visualConstraints = @[
-      formatString,
+      sharedVerticalConstraints,
       @"H:|-kHorizontalPadding-[primaryButton]-kHorizontalPadding-|"
     ];
     ApplyVisualConstraintsWithMetricsAndOptions(
         visualConstraints, views, metrics, NSLayoutFormatAlignAllCenterX);
 
     // Constraints for cold state mode.
     NSArray* coldStateVisualConstraints = @[
       @"V:[primaryButton]-kVerticalPaddingkButtonVerticalPadding-|",
       @"V:[imageView(kChromeImageFixedSize)]",
     ];
     _coldStateConstraints = VisualConstraintsWithMetrics(
         coldStateVisualConstraints, views, metrics);
 
     // Constraints for warm state mode.
-    formatString = @"V:[primaryButton]-kButtonVerticalPaddingx2-["
-                    "secondaryButton(kButtonHeight)]-"
-                    "kVerticalPaddingkButtonVerticalPadding-|";
+    NSString* warmStateVerticalConstraints =
+        @"V:[primaryButton]-kButtonVerticalPaddingx2-[secondaryButton("
+        @"kButtonHeight)]-kVerticalPaddingkButtonVerticalPadding-|";
     NSArray* warmStateVisualConstraints = @[
-      formatString,
+      warmStateVerticalConstraints,
       @"H:|-kHorizontalPadding-[secondaryButton]-kHorizontalPadding-|",
     ];
     _warmStateConstraints = VisualConstraintsWithMetrics(
         warmStateVisualConstraints, views, metrics);
 
     _mode = SigninPromoViewModeColdState;
     [self activateColdMode];
   }
   return self;
 }
@@ skipping 70 matching lines @@
                 target:self
               selector:@selector(accessibilitySecondaryAction:)];
   return @[ primaryCustomAction, secondaryCustomAction ];
 }
 
 - (NSString*)accessibilityLabel {
   return _textLabel.text;
 }
 
 @end