[ios clean] Fixes Toolbar constraints.

ios/clean/chrome/browser/ui/toolbar/toolbar_view_controller.mm

 // Copyright 2016 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/toolbar/toolbar_view_controller.h"
 
 #import "base/mac/foundation_util.h"
 #import "ios/clean/chrome/browser/ui/actions/tab_strip_actions.h"
 #import "ios/clean/chrome/browser/ui/commands/navigation_commands.h"
 #import "ios/clean/chrome/browser/ui/commands/tab_grid_commands.h"
@@ skipping 72 matching lines @@
   ]];
   self.stackView.translatesAutoresizingMaskIntoConstraints = NO;
   self.stackView.spacing = kStackViewSpacing;
   self.stackView.distribution = UIStackViewDistributionFill;
   [self updateAllButtonsVisibility];
 }
 
 - (void)setConstraints {
   [self.view setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
                                  UIViewAutoresizingFlexibleHeight];
-  [NSLayoutConstraint activateConstraints:@[
+  NSArray* constraints = @[
     [self.stackView.topAnchor constraintEqualToAnchor:self.view.topAnchor
                                              constant:kVerticalMargin],
     [self.stackView.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor
                                                 constant:-kVerticalMargin],
     [self.stackView.leadingAnchor
         constraintEqualToAnchor:self.view.leadingAnchor
                        constant:kHorizontalMargin],
     [self.stackView.trailingAnchor
         constraintEqualToAnchor:self.view.trailingAnchor
                        constant:-kHorizontalMargin],
     [self.progressBar.leadingAnchor
         constraintEqualToAnchor:self.view.leadingAnchor],
     [self.progressBar.trailingAnchor
         constraintEqualToAnchor:self.view.trailingAnchor],
     [self.progressBar.bottomAnchor
         constraintEqualToAnchor:self.view.bottomAnchor],
     [self.progressBar.heightAnchor
         constraintEqualToConstant:kProgressBarHeight],
-  ]];
+  ];
+
+  // Set the constraints priority to UILayoutPriorityDefaultHigh so these are
+  // not broken when the views are hidden or the VC's view size is 0.
+  [self activateConstraints:constraints
+               withPriority:UILayoutPriorityDefaultHigh];
 }
 
 - (void)viewWillTransitionToSize:(CGSize)size
        withTransitionCoordinator:
            (id<UIViewControllerTransitionCoordinator>)coordinator {
   // We need to dismiss the ToolsMenu everytime the Toolbar frame changes
   // (e.g. Size changes, rotation changes, etc.)
   [self.dispatcher closeToolsMenu];
 }
 
 #pragma mark - Components Setup
 
 - (void)setUpToolbarButtons {
+  NSMutableArray* buttonConstraints = [[NSMutableArray alloc] init];
+
   // Back button.
   self.backButton = [ToolbarButton backToolbarButton];
   self.backButton.visibilityMask = ToolbarComponentVisibilityCompactWidth |
                                    ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.backButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.backButton addTarget:self
                       action:@selector(goBack:)
             forControlEvents:UIControlEventTouchUpInside];
 
   // Forward button.
   self.forwardButton = [ToolbarButton forwardToolbarButton];
   self.forwardButton.visibilityMask =
       ToolbarComponentVisibilityCompactWidthOnlyWhenEnabled |
       ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.forwardButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.forwardButton addTarget:self
                          action:@selector(goForward:)
                forControlEvents:UIControlEventTouchUpInside];
 
   // Tab switcher Strip button.
   self.tabSwitchStripButton = [ToolbarButton tabSwitcherStripToolbarButton];
   self.tabSwitchStripButton.visibilityMask =
       ToolbarComponentVisibilityCompactWidth |
       ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.tabSwitchStripButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.tabSwitchStripButton addTarget:nil
                                 action:@selector(showTabStrip:)
                       forControlEvents:UIControlEventTouchUpInside];
 
   // Tab switcher Grid button.
   self.tabSwitchGridButton = [ToolbarButton tabSwitcherGridToolbarButton];
   self.tabSwitchGridButton.visibilityMask =
       ToolbarComponentVisibilityCompactWidth |
       ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.tabSwitchGridButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.tabSwitchGridButton addTarget:self
                                action:@selector(showTabGrid:)
                      forControlEvents:UIControlEventTouchUpInside];
   self.tabSwitchGridButton.hiddenInCurrentState = YES;
 
   // Tools menu button.
   self.toolsMenuButton = [ToolbarButton toolsMenuToolbarButton];
   self.toolsMenuButton.visibilityMask = ToolbarComponentVisibilityCompactWidth |
                                         ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.toolsMenuButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.toolsMenuButton addTarget:self
                            action:@selector(showToolsMenu:)
                  forControlEvents:UIControlEventTouchUpInside];
 
   // Share button.
   self.shareButton = [ToolbarButton shareToolbarButton];
   self.shareButton.visibilityMask = ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.shareButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.shareButton addTarget:self
                        action:@selector(showShareMenu:)
              forControlEvents:UIControlEventTouchUpInside];
 
   // Reload button.
   self.reloadButton = [ToolbarButton reloadToolbarButton];
   self.reloadButton.visibilityMask = ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.reloadButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.reloadButton addTarget:self
                         action:@selector(reload:)
               forControlEvents:UIControlEventTouchUpInside];
 
   // Stop button.
   self.stopButton = [ToolbarButton stopToolbarButton];
   self.stopButton.visibilityMask = ToolbarComponentVisibilityRegularWidth;
+  [buttonConstraints
+      addObject:[self.stopButton.widthAnchor
+                    constraintEqualToConstant:kToolbarButtonWidth]];
   [self.stopButton addTarget:self
                       action:@selector(stop:)
             forControlEvents:UIControlEventTouchUpInside];
+
+  // // Set the buttons constraints priority to UILayoutPriorityDefaultHigh so
+  // these are not broken when being hidden by the StackView.
+  [self activateConstraints:buttonConstraints
+               withPriority:UILayoutPriorityDefaultHigh];
 }
 
 - (void)setUpLocationBarContainer {
   UIView* locationBarContainer = [[UIView alloc] initWithFrame:CGRectZero];
   locationBarContainer.translatesAutoresizingMaskIntoConstraints = NO;
   locationBarContainer.backgroundColor = [UIColor whiteColor];
   locationBarContainer.layer.borderWidth = kLocationBarBorderWidth;
   locationBarContainer.layer.borderColor =
       [UIColor colorWithWhite:kLocationBarBorderColorBrightness alpha:1.0]
           .CGColor;
@@ skipping 149 matching lines @@
 // Updates all Buttons visibility to match any recent WebState change.
 - (void)updateAllButtonsVisibility {
   for (UIView* view in self.stackView.arrangedSubviews) {
     if ([view isKindOfClass:[ToolbarButton class]]) {
       ToolbarButton* button = base::mac::ObjCCastStrict<ToolbarButton>(view);
       [button setHiddenForCurrentStateAndSizeClass];
     }
   }
 }
 
+// Sets the priority for an array of constraints and activates them.
+- (void)activateConstraints:(NSArray*)constraintsArray
+               withPriority:(UILayoutPriority)priority {
+  for (NSLayoutConstraint* constraint in constraintsArray) {
+    constraint.priority = priority;
+  }
+  [NSLayoutConstraint activateConstraints:constraintsArray];
+}
+
 @end