no use readString16Inplace

This uses readString16Inplace, which we may try to remove, in order to
make it possible libbinder can use utf-8 internally (and save space).

Bug: 172502290
Test: boot
Change-Id: I7555abe63754ffb477f4fcd98e9bf886d3fba52e
diff --git a/camera/camera2/CaptureRequest.cpp b/camera/camera2/CaptureRequest.cpp
index 1843ec4..ebc09d7 100644
--- a/camera/camera2/CaptureRequest.cpp
+++ b/camera/camera2/CaptureRequest.cpp
@@ -94,12 +94,12 @@
     // Do not distinguish null arrays from 0-sized arrays.
     for (int32_t i = 0; i < size; ++i) {
         // Parcel.writeParcelableArray
-        size_t len;
-        const char16_t* className = parcel->readString16Inplace(&len);
+        std::optional<std::string> className;
+        parcel->readUtf8FromUtf16(&className);
         ALOGV("%s: Read surface class = %s", __FUNCTION__,
-              className != NULL ? String8(className).string() : "<null>");
+              className.value_or("<null>").c_str());
 
-        if (className == NULL) {
+        if (className == std::nullopt) {
             continue;
         }