[iOS] Update tab counts in tab grid page control.

This CL wires the tab grid page controls tab counts into the grid
view controllers. To do this, a public |itemCount| property is added to
the GridViewControllers, and the TabGridViewController updates the
counts in the page control whenever an event occurs that would change
the count (opening or closing a tab), and when the VC is initially set
up.

Bug: 804501, 804552
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I9162b45e04b102ce4c1b885356ebf3bf0873396b
Reviewed-on: https://chromium-review.googlesource.com/964143Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543716}

ios/chrome/browser/ui/tab_grid/grid_view_controller.h

@@ -40,6 +40,8 @@
 @property(nonatomic, strong) UIView* emptyStateView;
 // Returns YES if the grid has no items.
 @property(nonatomic, readonly, getter=isGridEmpty) BOOL gridEmpty;
+// The number of items in the grid. Not all of the items may be visible.
+@property(nonatomic, readonly) NSUInteger itemCount;
 // The visual look of the grid.
 @property(nonatomic, assign) GridTheme theme;
 // Delegate is informed of user interactions in the grid UI.

ios/chrome/browser/ui/tab_grid/grid_view_controller.mm

@@ -105,6 +105,10 @@ NSIndexPath* CreateIndexPath(NSInteger index) {
   return self.items.count == 0;
 }
 
+- (NSUInteger)itemCount {
+  return self.items.count;
+}
+
 - (BOOL)isSelectedCellVisible {
   if (self.collectionView.indexPathsForSelectedItems.count == 0)
     return NO;

ios/chrome/browser/ui/tab_grid/tab_grid_page_control.h

@@ -30,11 +30,11 @@
 // Setting this property will *not* update the selected page.
 @property(nonatomic, assign) CGFloat sliderPosition;
 
-// Text displayed next to the incognito and inside the regular tabs icons. The
-// available space for text is small -- no wider than two numerals. Text wider
-// than this will be clipped.
-@property(nonatomic, copy) NSString* incognitoText;
-@property(nonatomic, copy) NSString* regularText;
+// The numbers that the control should display in the appropriate sections.
+// Numbers less than 1 are not displayed.
+// Numbers greated than 99 are displayed as ':-)'.
+@property(nonatomic, assign) NSUInteger incognitoTabCount;
+@property(nonatomic, assign) NSUInteger regularTabCount;
 
 // Create and return a new instance of this control. This is the preferred way
 // to create instances of this class.

ios/chrome/browser/ui/tab_grid/tab_grid_page_control.mm

@@ -99,6 +99,15 @@ const int kBackgroundColor = 0x5F6368;
 CGPoint RectCenter(CGRect rect) {
   return CGPointMake(CGRectGetMidX(rect), CGRectGetMidY(rect));
 }
+
+// Returns the string to use for a numeric item count.
+NSString* StringForItemCount(long count) {
+  if (count == 0)
+    return @"";
+  if (count > 99)
+    return @":-)";
+  return [NSString stringWithFormat:@"%ld", count];
+}
 }
 
 // View class used for the background of this control; it draws the grey
@@ -138,8 +147,8 @@ CGPoint RectCenter(CGRect rect) {
 // Public properties
 @synthesize selectedPage = _selectedPage;
 @synthesize sliderPosition = _sliderPosition;
-@synthesize incognitoText = _incognitoText;
-@synthesize regularText = _regularText;
+@synthesize incognitoTabCount = _incognitoTabCount;
+@synthesize regularTabCount = _regularTabCount;
 // Private properties
 @synthesize incognitoGuide = _incognitoGuide;
 @synthesize regularGuide = _regularGuide;
@@ -192,16 +201,18 @@ CGPoint RectCenter(CGRect rect) {
 // the text in both labels (the regular and the  "selected" versions that's
 // visible when the slider is over a segment), and an ivar to store values that
 // are set before the labels are created.
-- (void)setIncognitoText:(NSString*)incognitoText {
+- (void)setIncognitoTabCount:(NSUInteger)incognitoTabCount {
+  NSString* incognitoText = StringForItemCount(incognitoTabCount);
   self.incognitoLabel.text = incognitoText;
   self.incognitoSelectedLabel.text = incognitoText;
-  _incognitoText = [incognitoText copy];
+  _incognitoTabCount = incognitoTabCount;
 }
 
-- (void)setRegularText:(NSString*)regularText {
+- (void)setRegularTabCount:(NSUInteger)regularTabCount {
+  NSString* regularText = StringForItemCount(regularTabCount);
   self.regularLabel.text = regularText;
   self.regularSelectedLabel.text = regularText;
-  _regularText = [regularText copy];
+  _regularTabCount = regularTabCount;
 }
 
 #pragma mark - Public methods
@@ -374,8 +385,8 @@ CGPoint RectCenter(CGRect rect) {
 
   // Update the label text, in case these properties have been set before the
   // views were set up.
-  self.regularText = _regularText;
-  self.incognitoText = _incognitoText;
+  self.regularTabCount = _regularTabCount;
+  self.incognitoTabCount = _incognitoTabCount;
 
   // Mark the control's layout as dirty so the the guides will be computed, then
   // force a layout now so it won't be triggered later (perhaps during an

ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.mm

@@ -427,6 +427,11 @@ typedef NS_ENUM(NSUInteger, TabGridConfiguration) {
   topToolbar.translatesAutoresizingMaskIntoConstraints = NO;
   [self.view addSubview:topToolbar];
   self.topToolbar = topToolbar;
+  // Configure and initialize the page control.
+  [self.topToolbar.pageControl addTarget:self
+                                  action:@selector(pageControlChanged:)
+                        forControlEvents:UIControlEventValueChanged];
+  [self updatePageControlItemCounts];
   NSArray* constraints = @[
     [topToolbar.topAnchor constraintEqualToAnchor:self.view.topAnchor],
     [topToolbar.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor],
@@ -550,12 +555,6 @@ typedef NS_ENUM(NSUInteger, TabGridConfiguration) {
   [self.newTabButton addTarget:self
                         action:@selector(newTabButtonTapped:)
               forControlEvents:UIControlEventTouchUpInside];
-  [self.topToolbar.pageControl addTarget:self
-                                  action:@selector(pageControlChanged:)
-                        forControlEvents:UIControlEventValueChanged];
-  // TODO(crbug.com/804501): Use the actual live tab counts.
-  self.topToolbar.pageControl.regularText = @"5";
-  self.topToolbar.pageControl.incognitoText = @"0";
   [self configureButtonsForCurrentPage];
 }
 
@@ -619,6 +618,13 @@ typedef NS_ENUM(NSUInteger, TabGridConfiguration) {
   }
 }
 
+- (void)updatePageControlItemCounts {
+  self.topToolbar.pageControl.incognitoTabCount =
+      self.incognitoTabsViewController.itemCount;
+  self.topToolbar.pageControl.regularTabCount =
+      self.regularTabsViewController.itemCount;
+}
+
 // Translates the toolbar views offscreen and then animates them back in using
 // the transition coordinator. Transitions are preferred here since they don't
 // interact with the layout system at all.
@@ -677,6 +683,7 @@ typedef NS_ENUM(NSUInteger, TabGridConfiguration) {
   } else if (gridViewController == self.incognitoTabsViewController) {
     [self.incognitoTabsDelegate closeItemAtIndex:index];
   }
+  [self updatePageControlItemCounts];
 }
 
 - (void)lastItemWasClosedInGridViewController:
@@ -687,6 +694,7 @@ typedef NS_ENUM(NSUInteger, TabGridConfiguration) {
 - (void)firstItemWasAddedInGridViewController:
     (GridViewController*)gridViewController {
   [self configureButtonsForCurrentPage];
+  [self updatePageControlItemCounts];
 }
 
 #pragma mark - Control actions
@@ -723,6 +731,7 @@ typedef NS_ENUM(NSUInteger, TabGridConfiguration) {
       // No-op. It is invalid to call insert new tab on remote tabs.
       break;
   }
+  [self updatePageControlItemCounts];
 }
 
 - (void)pageControlChanged:(id)sender {