Added customizable default system theme.

Bug: 29266591
Change-Id: If0945abbda9e3560af5a6cdef394296b23c6de0c
diff --git a/core/res/res/values-watch/themes_device_defaults.xml b/core/res/res/values-watch/themes_device_defaults.xml
index 879e02e..2313b26 100644
--- a/core/res/res/values-watch/themes_device_defaults.xml
+++ b/core/res/res/values-watch/themes_device_defaults.xml
@@ -38,4 +38,6 @@
         <item name="listPreferredItemPaddingEnd">?attr/dialogPreferredPadding</item>
     </style>
 
+    <!-- Use a dark theme for watches. -->
+    <style name="Theme.DeviceDefault.System" parent="Theme.Material" />
 </resources>
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index 8a88874..9985d8a 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -2188,6 +2188,7 @@
   <java-symbol type="style" name="TextAppearance.Material.TimePicker.TimeLabel" />
   <java-symbol type="attr" name="seekBarPreferenceStyle" />
   <java-symbol type="style" name="Theme.DeviceDefault.Resolver" />
+  <java-symbol type="style" name="Theme.DeviceDefault.System" />
   <java-symbol type="attr" name="preferenceActivityStyle" />
   <java-symbol type="attr" name="preferenceFragmentStyle" />
   <java-symbol type="bool" name="skipHoldBeforeMerge" />
diff --git a/core/res/res/values/themes_device_defaults.xml b/core/res/res/values/themes_device_defaults.xml
index 11bb106..ea1b626 100644
--- a/core/res/res/values/themes_device_defaults.xml
+++ b/core/res/res/values/themes_device_defaults.xml
@@ -551,4 +551,6 @@
         <item name="listPreferredItemPaddingEnd">?attr/dialogPreferredPadding</item>
     </style>
 
+    <!-- DeviceDefault theme for the default system theme.  -->
+    <style name="Theme.DeviceDefault.System" parent="Theme.Material.Light.DarkActionBar" />
 </resources>
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 107de8b..b21f5fb4 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -181,7 +181,7 @@
      * visual content.
      */
     private static final int DEFAULT_SYSTEM_THEME =
-            com.android.internal.R.style.Theme_DeviceDefault_Light_DarkActionBar;
+            com.android.internal.R.style.Theme_DeviceDefault_System;
 
     private final int mFactoryTestMode;
     private Timer mProfilerSnapshotTimer;