diff --git a/api/current.txt b/api/current.txt
index b9cd7d0..96058f1 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -29846,6 +29846,15 @@
     field public static final int THREAD_PRIORITY_URGENT_DISPLAY = -8; // 0xfffffff8
   }
 
+  public abstract class ProxyFileDescriptorCallback {
+    ctor public ProxyFileDescriptorCallback();
+    method public void onFsync() throws android.system.ErrnoException;
+    method public long onGetSize() throws android.system.ErrnoException;
+    method public int onRead(long, int, byte[]) throws android.system.ErrnoException;
+    method public abstract void onRelease();
+    method public int onWrite(long, int, byte[]) throws android.system.ErrnoException;
+  }
+
   public class RecoverySystem {
     method public static void installPackage(android.content.Context, java.io.File) throws java.io.IOException;
     method public static void rebootWipeCache(android.content.Context) throws java.io.IOException;
@@ -30263,6 +30272,7 @@
     method public boolean isEncrypted(java.io.File);
     method public boolean isObbMounted(java.lang.String);
     method public boolean mountObb(java.lang.String, java.lang.String, android.os.storage.OnObbStateChangeListener);
+    method public android.os.ParcelFileDescriptor openProxyFileDescriptor(int, android.os.ProxyFileDescriptorCallback) throws java.io.IOException;
     method public boolean unmountObb(java.lang.String, boolean, android.os.storage.OnObbStateChangeListener);
     field public static final java.lang.String ACTION_MANAGE_STORAGE = "android.os.storage.action.MANAGE_STORAGE";
   }
diff --git a/api/system-current.txt b/api/system-current.txt
index 75b0a34..20168b6 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -32448,6 +32448,15 @@
     field public static final int THREAD_PRIORITY_URGENT_DISPLAY = -8; // 0xfffffff8
   }
 
+  public abstract class ProxyFileDescriptorCallback {
+    ctor public ProxyFileDescriptorCallback();
+    method public void onFsync() throws android.system.ErrnoException;
+    method public long onGetSize() throws android.system.ErrnoException;
+    method public int onRead(long, int, byte[]) throws android.system.ErrnoException;
+    method public abstract void onRelease();
+    method public int onWrite(long, int, byte[]) throws android.system.ErrnoException;
+  }
+
   public class RecoverySystem {
     method public static void cancelScheduledUpdate(android.content.Context) throws java.io.IOException;
     method public static void installPackage(android.content.Context, java.io.File) throws java.io.IOException;
@@ -32951,6 +32960,7 @@
     method public boolean isEncrypted(java.io.File);
     method public boolean isObbMounted(java.lang.String);
     method public boolean mountObb(java.lang.String, java.lang.String, android.os.storage.OnObbStateChangeListener);
+    method public android.os.ParcelFileDescriptor openProxyFileDescriptor(int, android.os.ProxyFileDescriptorCallback) throws java.io.IOException;
     method public boolean unmountObb(java.lang.String, boolean, android.os.storage.OnObbStateChangeListener);
     field public static final java.lang.String ACTION_MANAGE_STORAGE = "android.os.storage.action.MANAGE_STORAGE";
   }
diff --git a/api/test-current.txt b/api/test-current.txt
index de86022..b361244 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -29956,6 +29956,15 @@
     field public static final int THREAD_PRIORITY_URGENT_DISPLAY = -8; // 0xfffffff8
   }
 
+  public abstract class ProxyFileDescriptorCallback {
+    ctor public ProxyFileDescriptorCallback();
+    method public void onFsync() throws android.system.ErrnoException;
+    method public long onGetSize() throws android.system.ErrnoException;
+    method public int onRead(long, int, byte[]) throws android.system.ErrnoException;
+    method public abstract void onRelease();
+    method public int onWrite(long, int, byte[]) throws android.system.ErrnoException;
+  }
+
   public class RecoverySystem {
     method public static void installPackage(android.content.Context, java.io.File) throws java.io.IOException;
     method public static void rebootWipeCache(android.content.Context) throws java.io.IOException;
@@ -30374,6 +30383,7 @@
     method public boolean isEncrypted(java.io.File);
     method public boolean isObbMounted(java.lang.String);
     method public boolean mountObb(java.lang.String, java.lang.String, android.os.storage.OnObbStateChangeListener);
+    method public android.os.ParcelFileDescriptor openProxyFileDescriptor(int, android.os.ProxyFileDescriptorCallback) throws java.io.IOException;
     method public boolean unmountObb(java.lang.String, boolean, android.os.storage.OnObbStateChangeListener);
     field public static final java.lang.String ACTION_MANAGE_STORAGE = "android.os.storage.action.MANAGE_STORAGE";
   }
diff --git a/core/java/android/os/ProxyFileDescriptorCallback.java b/core/java/android/os/ProxyFileDescriptorCallback.java
index 23848b9..2e9f8d9 100644
--- a/core/java/android/os/ProxyFileDescriptorCallback.java
+++ b/core/java/android/os/ProxyFileDescriptorCallback.java
@@ -21,7 +21,6 @@
 
 /**
  * Callback that handles file system requests from ProxyFileDescriptor.
- * @hide
  */
 public abstract class ProxyFileDescriptorCallback {
     /**
diff --git a/core/java/android/os/storage/StorageManager.java b/core/java/android/os/storage/StorageManager.java
index d5acbeb..85df48f 100644
--- a/core/java/android/os/storage/StorageManager.java
+++ b/core/java/android/os/storage/StorageManager.java
@@ -1327,6 +1327,7 @@
         }
     }
 
+
     /** {@hide} */
     @VisibleForTesting
     public @NonNull ParcelFileDescriptor openProxyFileDescriptor(
@@ -1378,7 +1379,19 @@
         throw new IOException("Failed to mount bridge.");
     }
 
-    /** {@hide} */
+    /**
+     * Opens seekable ParcelFileDescriptor that routes file operation requests to
+     * ProxyFileDescriptorCallback.
+     *
+     * @param mode The desired access mode, must be one of
+     *     {@link ParcelFileDescriptor#MODE_READ_ONLY},
+     *     {@link ParcelFileDescriptor#MODE_WRITE_ONLY}, or
+     *     {@link ParcelFileDescriptor#MODE_READ_WRITE}
+     * @param callback Callback to process file operation requests issued on returned file
+     *     descriptor. The callback is invoked on a thread managed by the framework.
+     * @return Seekable ParcelFileDescriptor.
+     * @throws IOException
+     */
     public @NonNull ParcelFileDescriptor openProxyFileDescriptor(
             int mode, ProxyFileDescriptorCallback callback)
                     throws IOException {