Refine Style/Grid picker recyclerview layout

 - Fix recyclerview's items not center aligned issue
 Before:
 https://screenshot.googleplex.com/7L8Q9hFDdeL.png
 https://screenshot.googleplex.com/ih5Ad7vxAeS.png
 After:
 https://screenshot.googleplex.com/8JFtHwvjy7s.png
 https://screenshot.googleplex.com/M9vjZrwdOik.png

 Bug: 160753361
 Test: manually, please check the screenshots

Change-Id: Icc277713571abda8d4537a8e6c09689445aba61c
diff --git a/res/layout/custom_theme_option.xml b/res/layout/custom_theme_option.xml
index 2805185..aff43a9 100644
--- a/res/layout/custom_theme_option.xml
+++ b/res/layout/custom_theme_option.xml
@@ -15,7 +15,7 @@
      limitations under the License.
 -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="wrap_content"
+    android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:paddingHorizontal="@dimen/option_padding_horizontal"
     android:paddingBottom="@dimen/option_bottom_margin"
diff --git a/res/layout/grid_option.xml b/res/layout/grid_option.xml
index 286c60b..d06ff60 100644
--- a/res/layout/grid_option.xml
+++ b/res/layout/grid_option.xml
@@ -15,9 +15,9 @@
      limitations under the License.
 -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="wrap_content"
+    android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:paddingRight="2dp"
+    android:paddingHorizontal="@dimen/option_padding_horizontal"
     android:paddingBottom="@dimen/option_bottom_margin"
     android:clipChildren="false"
     android:clipToPadding="false"
diff --git a/res/layout/theme_option.xml b/res/layout/theme_option.xml
index 379c507..bdf82d0 100644
--- a/res/layout/theme_option.xml
+++ b/res/layout/theme_option.xml
@@ -15,7 +15,7 @@
      limitations under the License.
 -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="wrap_content"
+    android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:paddingHorizontal="@dimen/option_padding_horizontal"
     android:paddingBottom="@dimen/option_bottom_margin"