Added End-of-Parcel check API.

Added End-of-Parcel check API, that verifies there are no
bytes left to be read on the Parcel.

Test: atest -d android.os.cts.ParcelTest#testEnforceNoDataAvail
Bug: 195622897
Bug: 204990745
Change-Id: I3068568d8d4371b071aecd357adeb45a2d7103e4

core/api/current.txt

@@ -31470,6 +31470,7 @@ package android.os {
     method public int dataPosition();
     method public int dataSize();
     method public void enforceInterface(@NonNull String);
+    method public void enforceNoDataAvail();
     method public boolean hasFileDescriptors();
     method public boolean hasFileDescriptors(int, int);
     method public byte[] marshall();

core/java/android/os/Parcel.java

@@ -845,6 +845,19 @@ public final class Parcel {
         nativeEnforceInterface(mNativePtr, interfaceName);
     }
 
+    /**
+     * Verify there are no bytes left to be read on the Parcel.
+     *
+     * @throws BadParcelableException If the current position hasn't reached the end of the Parcel.
+     * When used over binder, this exception should propagate to the caller.
+     */
+    public void enforceNoDataAvail() {
+        final int n = dataAvail();
+        if (n > 0) {
+            throw new BadParcelableException("Parcel data not fully consumed, unread size: " + n);
+        }
+    }
+
     /**
      * Writes the work source uid to the request headers.
      *