Update javadoc for DexUseManagerLocal and ArtManagerLocal.

Bug: 265897080
Test: N/A
Ignore-AOSP-First: ART Services.
Change-Id: Idff98a6f0493974d8f6e35e53f428d2b2c7392bb
diff --git a/libartservice/service/java/com/android/server/art/ArtManagerLocal.java b/libartservice/service/java/com/android/server/art/ArtManagerLocal.java
index baaf622..5066a9e 100644
--- a/libartservice/service/java/com/android/server/art/ArtManagerLocal.java
+++ b/libartservice/service/java/com/android/server/art/ArtManagerLocal.java
@@ -112,6 +112,16 @@
         mInjector = new Injector(this, null /* context */);
     }
 
+    /**
+     * Creates an instance.
+     *
+     * Only {@code SystemServer} should create an instance and register it in {@link
+     * LocalManagerRegistry}. Other API users should obtain the instance from {@link
+     * LocalManagerRegistry}.
+     *
+     * @param context the system server context
+     * @throws NullPointerException if required dependencies are missing
+     */
     public ArtManagerLocal(@NonNull Context context) {
         mInjector = new Injector(this, context);
     }
diff --git a/libartservice/service/java/com/android/server/art/DexUseManagerLocal.java b/libartservice/service/java/com/android/server/art/DexUseManagerLocal.java
index 996d087..acc9a16 100644
--- a/libartservice/service/java/com/android/server/art/DexUseManagerLocal.java
+++ b/libartservice/service/java/com/android/server/art/DexUseManagerLocal.java
@@ -124,7 +124,9 @@
      * PackageManagerService} starts because {@code PackageManagerService} needs it as soon as it
      * starts. It's safe to create an instance early because it doesn't depend on anything else.
      *
+     * @param context the system server context
      * @throws IllegalStateException if the instance is already created
+     * @throws NullPointerException if required dependencies are missing
      */
     @NonNull
     public static DexUseManagerLocal createInstance(@NonNull Context context) {