Centerize contents of contextual cards and remove white space.

Decrease the minHeight of the two buttons in the dismissal view and have
the contents centered.

Change-Id: I806e8ccae88e693dc222a13940597fd33684ee70
Fixes: 120086509
Test: visual

res/layout/homepage_dismissal_view.xml

@@ -40,6 +40,7 @@
             style="@style/ContextualCardDismissalButton"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
+            android:layout_marginBottom="@dimen/homepage_card_dismissal_margin_bottom"
             android:text="@string/contextual_card_dismiss_keep"/>
 
         <Button
@@ -47,6 +48,7 @@
             style="@style/ContextualCardDismissalButton"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
+            android:layout_marginBottom="@dimen/homepage_card_dismissal_margin_bottom"
             android:text="@string/contextual_card_dismiss_remove"/>
 
     </LinearLayout>

res/layout/homepage_slice_tile.xml

@@ -30,6 +30,7 @@
             android:id="@+id/slice_view"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
             android:paddingStart="@dimen/homepage_card_padding_start"
             android:paddingEnd="@dimen/homepage_card_padding_end"/>
 

res/values/dimens.xml

@@ -330,6 +330,7 @@
     <dimen name="homepage_half_card_padding_top">12dp</dimen>
     <dimen name="homepage_half_card_padding_bottom">16dp</dimen>
     <dimen name="homepage_half_card_title_margin_top">12dp</dimen>
+    <dimen name="homepage_card_dismissal_margin_bottom">2dp</dimen>
 
     <!-- Horizontal divider size and margin -->
     <dimen name="horizontal_divider_margin_top">4dp</dimen>

res/values/styles.xml

@@ -459,6 +459,7 @@
 
     <style name="ContextualCardDismissalButton"
            parent="android:Widget.DeviceDefault.Button.Borderless.Colored">
+        <item name="android:minHeight">16dp</item>
         <item name="android:textAllCaps">false</item>
     </style>