[ios] Fix TableViewTextLinkCell Label Spacing

- Increases top spacing to 13px
- Decreases bottom spacing to 0px so that the vertical spacing between footnote labels in Clear Browsing Data is not massive.

Screenshots: https://drive.google.com/open?id=12DY7uMoFwu0qpy93N3nUEdsBPIDeaJlQ, https://drive.google.com/open?id=1XARsG_J1dvUu1gSDVBJW4qTfPVMTp8mN

Bug: 863330
Change-Id: I92b7b4d09617353d6ccba088ea8fa3675b32c986
Reviewed-on: https://chromium-review.googlesource.com/1141056Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575851}

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

@@ -32,6 +32,6 @@ extern const CGFloat kTableViewHighlightedCellColorAlpha;
 extern const CGFloat kUseDefaultFontSize;
 
 // Spacing between text label and cell contentView.
-extern const CGFloat kTableViewLabelVerticalSpacing;
+extern const CGFloat kTableViewLabelVerticalTopSpacing;
 
 #endif  // IOS_CHROME_BROWSER_UI_TABLE_VIEW_CELLS_TABLE_VIEW_CELLS_CONSTANTS_H_

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

@@ -16,4 +16,4 @@ const CGFloat kTableViewCellSelectionAnimationDuration = 0.15;
 const CGFloat kTableViewHighlightedCellColor = 0xA6A6A6;
 const CGFloat kTableViewHighlightedCellColorAlpha = 0.5;
 const CGFloat kUseDefaultFontSize = 0.0;
-const CGFloat kTableViewLabelVerticalSpacing = 4.0;
+const CGFloat kTableViewLabelVerticalTopSpacing = 13.0;

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

@@ -85,10 +85,10 @@ const CGFloat kTextCellLinkColor = 0x1A73E8;
                          constant:kTableViewHorizontalSpacing],
       [_textLabel.topAnchor
           constraintEqualToAnchor:self.contentView.topAnchor
-                         constant:kTableViewLabelVerticalSpacing],
+                         constant:kTableViewLabelVerticalTopSpacing],
       [_textLabel.bottomAnchor
           constraintEqualToAnchor:self.contentView.bottomAnchor
-                         constant:-kTableViewLabelVerticalSpacing],
+                         constant:0],
       [_textLabel.trailingAnchor
           constraintEqualToAnchor:self.contentView.trailingAnchor
                          constant:-kTableViewHorizontalSpacing]