Use a margin to make the title bar stay the same size while loading.

Allows title_bar to use wrap_content, and therefore be able to show
multiple lines of text in voice search mode.

Fixes http://b/issue?id=2510376

Change-Id: If196f63577b6606be0129ee224842dc858f5931a
diff --git a/res/layout/title_bar.xml b/res/layout/title_bar.xml
index 22ab6e4..3765024 100644
--- a/res/layout/title_bar.xml
+++ b/res/layout/title_bar.xml
@@ -15,12 +15,9 @@
    limitations under the License.
 -->
 
-<!-- Manually set the height, to ensure that it matches the SearchDialog's
-        height.  It also ensures that when the stop button is showing it does
-        not change its height. -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="57dip"
+    android:layout_height="wrap_content"
     android:orientation="vertical"
     android:paddingLeft="8dip"
     android:paddingRight="12dip"