Add search bar to SearchActivity.

Styling doesn't look exactly right yet but there's a bar.
Creates an ItemDecoration to add a spacer above the first view.

Removes the action bar and replaces it with a SearchView
inside of a CardView.

Remaining work: pixel pushing

Bug: 37477506
Test: make RunSettingsRoboTests
Change-Id: Ibf38c3c2725551bc4cd90e98d0020ec49c2eab2b
Merged-In: I4a0f0c91c51ff5820b61a596520d80a3337c3466

res/values/themes.xml

@@ -165,6 +165,12 @@
         <item name="switchBarTheme">@style/ThemeOverlay.SwitchBar.SubSettings</item>
     </style>
 
+    <!-- Variant of the settings theme with no action bar. -->
+    <style name="Theme.Settings.NoActionBar">
+        <item name="android:windowActionBar">false</item>
+        <item name="android:windowNoTitle">true</item>
+    </style>
+
     <style name="Theme.ProvisioningActivity" parent="@android:style/Theme.Translucent.NoTitleBar">
         <item name="android:windowAnimationStyle">@null</item>
         <item name="android:windowIsTranslucent">true</item>