ZipUtils: use FileChannel#size

RandomAccessFile#length returns 0 for block devices while
FileChannel#size returns the correct size. ZipUtils should work with
block-device zip files when Android is running as a guest OS and
APK/APEX files are passed via block devices.

Bug: 193592496
Bug: 192366904
Test: FrameworksServicesTests
Change-Id: I6472e2a9051b92a5a778b4990b8e681492985d1a

core/java/android/util/apk/ZipUtils.java

@@ -63,7 +63,8 @@ abstract class ZipUtils {
         // exactly the remaining bytes in the buffer. The search is bounded because the maximum
         // size of the comment field is 65535 bytes because the field is an unsigned 16-bit number.
 
-        long fileSize = zip.length();
+        // TODO(b/193592496) RandomAccessFile#length
+        long fileSize = zip.getChannel().size();
         if (fileSize < ZIP_EOCD_REC_MIN_SIZE) {
             return null;
         }
@@ -110,7 +111,8 @@ abstract class ZipUtils {
             throw new IllegalArgumentException("maxCommentSize: " + maxCommentSize);
         }
 
-        long fileSize = zip.length();
+        // TODO(b/193592496) RandomAccessFile#length
+        long fileSize = zip.getChannel().size();
         if (fileSize < ZIP_EOCD_REC_MIN_SIZE) {
             // No space for EoCD record in the file.
             return null;