Make the bookmark thumbnails larger.

Change-Id: I33e72e55e0cad9c73b3c50cb30277ed22eb511cb
diff --git a/res/values/dimensions.xml b/res/values/dimensions.xml
index 2fc3233..4d19a9f 100644
--- a/res/values/dimensions.xml
+++ b/res/values/dimensions.xml
@@ -18,4 +18,7 @@
     <!-- The width of an unselected tab -->
     <dimen
         name="tab_width_unselected">300dp</dimen>
+
+    <dimen name="bookmarkThumbnailWidth">90dip</dimen>
+    <dimen name="bookmarkThumbnailHeight">80dip</dimen>
 </resources>
\ No newline at end of file