[ios] Adds a highlight tap animation to TableViewTextHeaderFooterView

Bug: 822987
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I7aa275e08846b1ea9b067de343f6a631a56db566
Reviewed-on: https://chromium-review.googlesource.com/972163
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546154}

ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_table_view_controller.mm

@@ -5,6 +5,7 @@
 #import "ios/chrome/browser/ui/ntp/recent_tabs/recent_tabs_table_view_controller.h"
 
 #include "base/logging.h"
+#include "base/mac/foundation_util.h"
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/strings/sys_string_conversions.h"
@@ -769,6 +770,15 @@ const int kRelativeTimeMaxHours = 4;
   if (tapGesture.state == UIGestureRecognizerStateEnded) {
     [self toggleExpansionOfSectionIdentifier:
               self.lastTappedHeaderSectionIdentifier];
+
+    // Highlight the section header being tapped.
+    NSInteger section = [self.tableViewModel
+        sectionForSectionIdentifier:self.lastTappedHeaderSectionIdentifier];
+    UITableViewHeaderFooterView* headerView =
+        [self.tableView headerViewForSection:section];
+    TableViewTextHeaderFooterView* headerTextView =
+        base::mac::ObjCCastStrict<TableViewTextHeaderFooterView>(headerView);
+    [headerTextView animateHighlight];
   }
 }
 
@@ -817,6 +827,15 @@ const int kRelativeTimeMaxHours = 4;
       return;
     }
 
+    // Highlight the section header being long pressed.
+    NSInteger section = [self.tableViewModel
+        sectionForSectionIdentifier:self.lastTappedHeaderSectionIdentifier];
+    UITableViewHeaderFooterView* headerView =
+        [self.tableView headerViewForSection:section];
+    TableViewTextHeaderFooterView* headerTextView =
+        base::mac::ObjCCastStrict<TableViewTextHeaderFooterView>(headerView);
+    [headerTextView animateHighlight];
+
     web::ContextMenuParams params;
     // Get view coordinates in local space.
     CGPoint viewCoordinate = [longPressGesture locationInView:self.tableView];

ios/chrome/browser/ui/table_view/cells/table_view_text_header_footer_item.h

@@ -19,6 +19,9 @@
 // UITableViewHeaderFooterView that displays a text label.
 @interface TableViewTextHeaderFooterView : UITableViewHeaderFooterView
 @property(nonatomic, readwrite, strong) UILabel* subtitleLabel;
+// Animates a change in the backgroundView color and then changes it back to the
+// original backGround color in order to simulate a selection highlight.
+- (void)animateHighlight;
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_TABLE_VIEW_CELLS_TABLE_VIEW_TEXT_HEADER_FOOTER_ITEM_H_

ios/chrome/browser/ui/table_view/cells/table_view_text_header_footer_item.mm

@@ -48,7 +48,13 @@ const CGFloat kVerticalSpacing = 2.0;
 
 #pragma mark - TableViewTextHeaderFooter
 
+@interface TableViewTextHeaderFooterView ()
+// Animator that handles all cell animations.
+@property(strong, nonatomic) UIViewPropertyAnimator* cellAnimator;
+@end
+
 @implementation TableViewTextHeaderFooterView
+@synthesize cellAnimator = _cellAnimator;
 @synthesize subtitleLabel = _subtitleLabel;
 @synthesize textLabel = _textLabel;
 
@@ -108,4 +114,26 @@ const CGFloat kVerticalSpacing = 2.0;
   return self;
 }
 
+- (void)animateHighlight {
+  UIColor* originalBackgroundColor = self.contentView.backgroundColor;
+  self.cellAnimator = [[UIViewPropertyAnimator alloc]
+      initWithDuration:0.15
+                 curve:UIViewAnimationCurveLinear
+            animations:^{
+              self.contentView.backgroundColor =
+                  [[UIColor lightGrayColor] colorWithAlphaComponent:0.5];
+            }];
+  __weak TableViewTextHeaderFooterView* weakSelf = self;
+  [self.cellAnimator addCompletion:^(UIViewAnimatingPosition finalPosition) {
+    weakSelf.contentView.backgroundColor = originalBackgroundColor;
+  }];
+  [self.cellAnimator startAnimation];
+}
+
+- (void)prepareForReuse {
+  [super prepareForReuse];
+  if (self.cellAnimator.isRunning)
+    [self.cellAnimator stopAnimation:YES];
+}
+
 @end