Adding VisualConstraintsWithMetricsAndOptions()

ios/chrome/browser/ui/uikit_ui_util.mm

 // Copyright 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 "ios/chrome/browser/ui/uikit_ui_util.h"
 
 #import <Accelerate/Accelerate.h>
 #import <Foundation/Foundation.h>
 #import <QuartzCore/QuartzCore.h>
 #include <stddef.h>
@@ skipping 552 matching lines @@
                                        NSDictionary* metrics,
                                        UIView* unused_parentView) {
   ApplyVisualConstraintsWithMetrics(constraints, subviewsDictionary, metrics);
 }
 
 void ApplyVisualConstraintsWithMetricsAndOptions(
     NSArray* constraints,
     NSDictionary* subviewsDictionary,
     NSDictionary* metrics,
     NSLayoutFormatOptions options) {
-  NSMutableArray* layoutConstraints =
-      [NSMutableArray arrayWithCapacity:constraints.count * 3];
-  for (NSString* constraint in constraints) {
-    DCHECK([constraint isKindOfClass:[NSString class]]);
-    [layoutConstraints addObjectsFromArray:
-                           [NSLayoutConstraint
-                               constraintsWithVisualFormat:constraint
-                                                   options:options
-                                                   metrics:metrics
-                                                     views:subviewsDictionary]];
-  }
+  NSArray* layoutConstraints = VisualConstraintsWithMetricsAndOptions(
+      constraints, subviewsDictionary, metrics, options);
   [NSLayoutConstraint activateConstraints:layoutConstraints];
 }
 
 void ApplyVisualConstraintsWithMetricsAndOptions(
     NSArray* constraints,
     NSDictionary* subviewsDictionary,
     NSDictionary* metrics,
     NSLayoutFormatOptions options,
     UIView* unused_parentView) {
   ApplyVisualConstraintsWithMetricsAndOptions(constraints, subviewsDictionary,
                                               metrics, options);
 }
 
+NSArray* VisualConstraintsWithMetrics(NSArray* constraints,
+                                      NSDictionary* subviewsDictionary,
+                                      NSDictionary* metrics) {
+  return VisualConstraintsWithMetricsAndOptions(constraints, subviewsDictionary,
+                                                metrics, 0);
+}
+
+NSArray* VisualConstraintsWithMetricsAndOptions(
+    NSArray* constraints,
+    NSDictionary* subviewsDictionary,
+    NSDictionary* metrics,
+    NSLayoutFormatOptions options) {
+  NSMutableArray* layoutConstraints =
+      [NSMutableArray arrayWithCapacity:constraints.count * 3];

[lpromero, 2017/03/28 11:10:07]

Question for marq: I don't understand the 3. Is it deterministic? A single
visual format string can output way more than 3 constraints.

[marq (ping after 24h), 2017/03/28 12:15:13]

No, it was an estimate. It should probably be documented or just removed, since
I don't know at what point the capacity estimates become optimizations.

[jlebel, 2017/03/29 10:47:17]

Removed as talk offline.

+  for (NSString* constraint in constraints) {
+    DCHECK([constraint isKindOfClass:[NSString class]]);
+    [layoutConstraints addObjectsFromArray:
+                           [NSLayoutConstraint
+                               constraintsWithVisualFormat:constraint
+                                                   options:options
+                                                   metrics:metrics
+                                                     views:subviewsDictionary]];
+  }
+  return layoutConstraints;

[marq (ping after 24h), 2017/03/28 12:15:13]

Missed this: this should return [layoutConstrains copy], so it returns an
immutable array without keeping the mutable array overhead around for no reason.

[jlebel, 2017/03/29 10:47:17]

Done.

+}
+
 void AddSameCenterConstraints(UIView* view1, UIView* view2) {
   AddSameCenterXConstraint(view1, view2);
   AddSameCenterYConstraint(view1, view2);
 }
 
 void AddSameCenterXConstraint(UIView* view1, UIView* view2) {
   [view1.centerXAnchor constraintEqualToAnchor:view2.centerXAnchor].active =
       YES;
 }
 
@@ skipping 77 matching lines @@
 
 // On iOS10 and above, trigger a haptic vibration for a notification.
 // This is a no-op for devices that do not support it.
 void TriggerHapticFeedbackForNotification(UINotificationFeedbackType type) {
   if (base::ios::IsRunningOnIOS10OrLater()) {
     UINotificationFeedbackGenerator* generator =
         [[UINotificationFeedbackGenerator alloc] init];
     [generator notificationOccurred:type];
   }
 }