Always reserve space for preference icons.

This aligns text on preferences on the same screen when some of them
don't have icons.

- Use a custom layout for
  preference
  EditPreference
  switch preference
  VolumeSeekPreference
  DialogPreferencei
  Restricted*Preference
  DropdownPreference

- Moved related style defs into a new file styles_preference.xml,
  because current styles file is too large to read.
- Switch <PreferenceScreen ...> to <Preference ...> for a bunch of
  regular preferences.
- Also removed some dead style.

Bug: 33430928
Test: runtest --path packages/apps/Settings/tests/app/src/com/android/settings/dashboard/PreferenceThemeTest.java

Change-Id: Ic9b75d3f133f2a83cd999297b8596253d4b10161
diff --git a/res/xml/sound_settings.xml b/res/xml/sound_settings.xml
index 227a650..c74d1f1 100644
--- a/res/xml/sound_settings.xml
+++ b/res/xml/sound_settings.xml
@@ -16,9 +16,9 @@
 
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
                   xmlns:settings="http://schemas.android.com/apk/res/com.android.settings"
-        android:title="@string/sound_settings"
-        android:key="sound_settings"
-        settings:keywords="@string/keywords_sounds">
+          android:title="@string/sound_settings"
+          android:key="sound_settings"
+          settings:keywords="@string/keywords_sounds">
 
         <!-- Media volume -->
         <com.android.settings.notification.VolumeSeekBarPreference
@@ -87,7 +87,7 @@
                 android:key="cell_broadcast_settings"
                 android:title="@string/cell_broadcast_settings"
                 settings:useAdminDisabledSummary="true">
-                <intent
+                    <intent
                         android:action="android.intent.action.MAIN"
                         android:targetPackage="com.android.cellbroadcastreceiver"
                         android:targetClass="com.android.cellbroadcastreceiver.CellBroadcastSettings" />
@@ -101,7 +101,7 @@
                 android:fragment="com.android.settings.notification.OtherSoundSettings" />
 
         <!-- Cast -->
-        <PreferenceScreen
+        <Preference
                 android:key="wifi_display"
                 android:title="@string/wifi_display_settings_title"
                 android:fragment="com.android.settings.wfd.WifiDisplaySettings" />