Part of fix for libmedia OOB write anywhere

Clarify that decrypt destination is not a pointer for
secure case.

b/23223325

Change-Id: I642dcf790a9eb9e32175f3e0d8f040c82228e3ac
diff --git a/media/libmedia/ICrypto.cpp b/media/libmedia/ICrypto.cpp
index 2f440fe..947294f 100644
--- a/media/libmedia/ICrypto.cpp
+++ b/media/libmedia/ICrypto.cpp
@@ -293,9 +293,9 @@
                     subSamples,
                     sizeof(CryptoPlugin::SubSample) * numSubSamples);
 
-            void *dstPtr;
+            void *secureBufferId, *dstPtr;
             if (secure) {
-                dstPtr = reinterpret_cast<void *>(static_cast<uintptr_t>(data.readInt64()));
+                secureBufferId = reinterpret_cast<void *>(static_cast<uintptr_t>(data.readInt64()));
             } else {
                 dstPtr = malloc(totalSize);
             }
@@ -313,7 +313,7 @@
                     mode,
                     sharedBuffer, offset,
                     subSamples, numSubSamples,
-                    dstPtr,
+                    secure ? secureBufferId : dstPtr,
                     &errorDetailMsg);
             }