Replace basic_string<uint8_t> with std::vector

In newer versions of libc++, std::char_traits<T> is no longer defined
for non-character types, and a result, std::basic_string<uint8_t> is
also no longer defined. See
https://discourse.llvm.org/t/deprecating-std-string-t-for-non-character-t/66779.

Bug: 175635923
Test: make checkbuild
Change-Id: I1893d1b1419f528115739275ca0f1d80ddb22470
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index b84079a..8a62ebe 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -925,7 +925,7 @@
 protected:
     // StreamHalInterfaceCodecFormatCallback implementation
                 void        onCodecFormatChanged(
-            const std::basic_string<uint8_t>& metadataBs) final;
+            const std::vector<uint8_t>& metadataBs) final;
 
     // ThreadBase virtuals
     void preExit() final EXCLUDES_ThreadBase_Mutex;