Bug 1202870 - Set toolbar menu row height to 48dp. r=mhaigh

I tried to use the `?android:attr/...` method listed in the nearby comments but
kept receiving a "ResourceNotFound" exception. I wonder if this is related to
the way we inherit and then override the themes.

--HG--
extra : commitid : 6G6nTr4Sfrv
extra : rebase_source : 1ba4aab60e3a9cf3423b0297bd643055f9f1b28d

mobile/android/base/resources/values-v11/dimens.xml

@@ -8,6 +8,6 @@
     <!-- This is chosen to be close to Android's listPreferredItemHeightSmall.
          TODO: We should inherit these from the system.
          http://androidxref.com/4.2.2_r1/xref/frameworks/base/core/res/res/values/themes.xml#1287 -->
-    <dimen name="menu_item_row_height">44dp</dimen>
+    <dimen name="menu_item_row_height">48dp</dimen>
 
 </resources>