UI for switching texture upload mode

For browser, default will be CPU upload until bug 5334978 fix.

bug:5347539

The webkit part is in
https://android-git.corp.google.com/g/#/c/137610/

Change-Id: Iec3a100dc142b28e54145f08a5c76210f8634cba
diff --git a/res/xml/debug_preferences.xml b/res/xml/debug_preferences.xml
index 2d15ab2..abbd07e 100644
--- a/res/xml/debug_preferences.xml
+++ b/res/xml/debug_preferences.xml
@@ -39,6 +39,11 @@
         android:defaultValue="false"
         android:title="@string/pref_development_visual_indicator" />
 
+    <CheckBoxPreference
+        android:key="enable_cpu_upload_path"
+        android:defaultValue="true"
+        android:title="@string/pref_development_cpu_upload_path" />
+
     <!-- The javascript console is enabled by default when the user has
          also enabled debug mode by navigating to about:debug. -->
     <CheckBoxPreference