Add MtpDevice#getPartialObject64 method.

This is the method similar to getPartialObject but takes uint64_t as
offset.

BUG=26703522

Change-Id: I9b8b5f77225b744b527c4a78fe628e88ae89209f
diff --git a/media/mtp/MtpDevice.h b/media/mtp/MtpDevice.h
index edc608f..ce60811 100644
--- a/media/mtp/MtpDevice.h
+++ b/media/mtp/MtpDevice.h
@@ -118,6 +118,12 @@
                                               uint32_t *writtenSize,
                                               ReadObjectCallback callback,
                                               void* clientData);
+    bool                    readPartialObject64(MtpObjectHandle handle,
+                                                uint64_t offset,
+                                                uint32_t size,
+                                                uint32_t *writtenSize,
+                                                ReadObjectCallback callback,
+                                                void* clientData);
     // Starts a request to read MTP event from MTP device. It returns a request handle that
     // can be used for blocking read or cancel. If other thread has already been processing an
     // event returns -1.