DropBox: Read until the end of stream has been reached

Read the requested length or until the end of the input stream
has actually been reached.

Change-Id: I01bc0b81eca0225209bdd288dde6a778a19d1e2c

core/java/android/os/DropBoxManager.java

@@ -150,7 +150,12 @@ public class DropBoxManager {
             try {
                 is = getInputStream();
                 byte[] buf = new byte[maxBytes];
-                return new String(buf, 0, Math.max(0, is.read(buf)));
+                int readBytes = 0;
+                int n = 0;
+                while (n >= 0 && (readBytes += n) < maxBytes) {
+                    n = is.read(buf, readBytes, maxBytes - readBytes);
+                }
+                return new String(buf, 0, readBytes);
             } catch (IOException e) {
                 return null;
             } finally {