[Multipaste] Adjust the content's top/bottom padding size

Besides the content padding, this CL corrects the label's height to
ensure that the total height of a label menu item is 36.

Bug: 1159706
Change-Id: Ibb1718262f3bdce3e031e04fb34db629b8ff01b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2605392
Commit-Queue: Andrew Xu <andrewxu@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839484}

ash/clipboard/views/clipboard_history_view_constants.h

@@ -11,7 +11,7 @@ namespace ash {
 namespace ClipboardHistoryViews {
 
 // The insets within the contents view.
-constexpr int kContentsVerticalInset = 4;
+constexpr int kContentsVerticalInset = 8;
 constexpr gfx::Insets kContentsInsets(kContentsVerticalInset,
                                       /*horizontal=*/16);
 
@@ -29,7 +29,7 @@ constexpr gfx::Insets kBitmapItemDeleteButtonMargins =
     gfx::Insets(/*top=*/4, /*left=*/0, /*bottom=*/0, /*right=*/4);
 
 // The preferred height of `ClipboardHistoryLabel`.
-constexpr int kLabelPreferredHeight = 28;
+constexpr int kLabelPreferredHeight = 20;
 
 // The preferred height of the image view showing on
 // `ClipboardHistoryBitmapItemView`.