aaudio: use unique_ptr in FixedBlockAdapter

Code cleanup.

Bug: 151650670
Test: atest CtsNativeMediaAAudioTestCases
Change-Id: I980862379ade9b6cc62f1743c916208e3911a00a
Merged-In: I980862379ade9b6cc62f1743c916208e3911a00a
(cherry picked from commit 2f39c0b0fcbc5b857df2823247d163f2ba1c14a8)
diff --git a/media/libaaudio/src/utility/FixedBlockWriter.cpp b/media/libaaudio/src/utility/FixedBlockWriter.cpp
index 2ce8046..afb83c1 100644
--- a/media/libaaudio/src/utility/FixedBlockWriter.cpp
+++ b/media/libaaudio/src/utility/FixedBlockWriter.cpp
@@ -30,7 +30,7 @@
     if (bytesToStore > roomAvailable) {
         bytesToStore = roomAvailable;
     }
-    memcpy(mStorage + mPosition, buffer, bytesToStore);
+    memcpy(&mStorage[mPosition], buffer, bytesToStore);
     mPosition += bytesToStore;
     return bytesToStore;
 }
@@ -46,7 +46,7 @@
         bytesLeft -= bytesWritten;
         // If storage full then flush it out
         if (mPosition == mSize) {
-            result = mFixedBlockProcessor.onProcessFixedBlock(mStorage, mSize);
+            result = mFixedBlockProcessor.onProcessFixedBlock(mStorage.get(), mSize);
             mPosition = 0;
         }
     }