Migrate ColorExtractionService to JobService

IntentService cannot be run in the background, so moving to
JobService prevents us from crashing if the wallpaper is
changed while we aren't running.

Bug: 62065291
Change-Id: Ie0c887e36d0ced43a0b9ab8136bf55eb37697489

src/com/android/launcher3/Utilities.java

@@ -61,7 +61,6 @@ import java.lang.reflect.Method;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Locale;
-import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
@@ -110,6 +109,8 @@ public final class Utilities {
     // An intent extra to indicate the horizontal scroll of the wallpaper.
     public static final String EXTRA_WALLPAPER_OFFSET = "com.android.launcher3.WALLPAPER_OFFSET";
 
+    public static final int COLOR_EXTRACTION_JOB_ID = 1;
+
     // These values are same as that in {@link AsyncTask}.
     private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
     private static final int CORE_POOL_SIZE = CPU_COUNT + 1;