Add wallpaper controlling system apis.

Change-Id: Ibaa8009e9b9d2e58254a4d9107a316c7f1de2211

api/system-current.txt

@@ -5327,6 +5327,7 @@ package android.app {
 
   public class WallpaperManager {
     method public void clear() throws java.io.IOException;
+    method public void clearWallpaper();
     method public void clearWallpaperOffsets(android.os.IBinder);
     method public void forgetLoadedWallpaper();
     method public android.graphics.drawable.Drawable getBuiltInDrawable();
@@ -5347,6 +5348,7 @@ package android.app {
     method public void setDisplayPadding(android.graphics.Rect);
     method public void setResource(int) throws java.io.IOException;
     method public void setStream(java.io.InputStream) throws java.io.IOException;
+    method public boolean setWallpaperComponent(android.content.ComponentName);
     method public void setWallpaperOffsetSteps(float, float);
     method public void setWallpaperOffsets(android.os.IBinder, float, float);
     method public void suggestDesiredDimensions(int, int);

core/java/android/app/WallpaperManager.java

@@ -993,6 +993,47 @@ public class WallpaperManager {
         }
     }
 
+    /**
+     * Clear the wallpaper.
+     *
+     * @hide
+     */
+    @SystemApi
+    public void clearWallpaper() {
+        if (sGlobals.mService == null) {
+            Log.w(TAG, "WallpaperService not running");
+            return;
+        }
+        try {
+            sGlobals.mService.clearWallpaper();
+        } catch (RemoteException e) {
+            // Ignore
+        }
+    }
+
+    /**
+     * Set the live wallpaper.
+     *
+     * This can only be called by packages with android.permission.SET_WALLPAPER_COMPONENT
+     * permission.
+     *
+     * @hide
+     */
+    @SystemApi
+    public boolean setWallpaperComponent(ComponentName name) {
+        if (sGlobals.mService == null) {
+            Log.w(TAG, "WallpaperService not running");
+            return false;
+        }
+        try {
+            sGlobals.mService.setWallpaperComponent(name);
+            return true;
+        } catch (RemoteException e) {
+            // Ignore
+        }
+        return false;
+    }
+
     /**
      * Set the position of the current wallpaper within any larger space, when
      * that wallpaper is visible behind the given window.  The X and Y offsets