Add CAPTURE_BLACKOUT_CONTENT permission

Added a permssion to allow an application to capture screenshots of
layers that would normally be blacked out.

Test: Builds, screenshots still work as before
Test: ScreenshotTests
Bug: 173746627
Change-Id: I27237c8e340904cbaa82c7e5793de35cab85d8de
diff --git a/libs/WindowManager/Shell/AndroidManifest.xml b/libs/WindowManager/Shell/AndroidManifest.xml
index 6bd0e0a..10df726 100644
--- a/libs/WindowManager/Shell/AndroidManifest.xml
+++ b/libs/WindowManager/Shell/AndroidManifest.xml
@@ -18,6 +18,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.android.wm.shell">
     <!-- System permission required by WM Shell Task Organizer. -->
+    <uses-permission android:name="android.permission.CAPTURE_BLACKOUT_CONTENT" />
     <uses-permission android:name="android.permission.INTERACT_ACROSS_USERS" />
     <uses-permission android:name="android.permission.ROTATE_SURFACE_FLINGER" />
     <uses-permission android:name="android.permission.READ_FRAME_BUFFER" />