Respond to API council feedback.

Move aggressive allocation to @SystemApi, which means we can hide
the "flags" API variants.

Remove UUID APIs, since we should use existing Serializable APIs.

Relax permission checks to allow apps to ask for their own stats.

Improve docs.

Test: cts-tradefed run commandAndExit cts-dev -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.StorageHostTest
Bug: 37534687, 37534941, 37718184, 37738770
Change-Id: I6a763fb3ab3169c8d3329765bb31e1ee08d9ced7
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 3131302..7c7daf7 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -1697,7 +1697,8 @@
     <permission android:name="android.permission.CACHE_CONTENT"
         android:protectionLevel="signature" />
 
-    <!-- Allows an application to aggressively allocate disk space.
+    <!-- @SystemApi @hide
+         Allows an application to aggressively allocate disk space.
          <p>Not for use by third-party applications.
     -->
     <permission android:name="android.permission.ALLOCATE_AGGRESSIVE"