Use explicit requirements from APEX

Previously, CAS APEX used ":sphal" and `android_load_sphal_library` to
open plugins from /vendor/lib/mediacas. It was a workaround because
there's no way to limit the scope to /vendor/lib/mediacas. And CAS
plugins are not SPHAL libraries.

Now, the APEX uses more explicit requirements: ":mediacas", which
limitss the scope to /vendor/lib/mediacas.

Bug: 298542407
Test: atest CtsMediaMiscTestCases:MediaCasTest
Change-Id: Id91a87e0f6ef8a761e37cabed7da8b9fed0591c2

cas/aidl/default/Android.bp

@@ -57,7 +57,6 @@ cc_defaults {
     shared_libs: [
         "libbinder_ndk",
         "liblog",
-        "libvndksupport",
     ],
     header_libs: ["media_plugin_headers"],
 }

cas/aidl/default/SharedLibrary.cpp

@@ -19,7 +19,6 @@
 #include "SharedLibrary.h"
 #include <dlfcn.h>
 #include <utils/Log.h>
-#include <vndksupport/linker.h>
 
 namespace aidl {
 namespace android {
@@ -27,12 +26,12 @@ namespace hardware {
 namespace cas {
 
 SharedLibrary::SharedLibrary(const String8& path) {
-    mLibHandle = android_load_sphal_library(path.c_str(), RTLD_NOW);
+    mLibHandle = dlopen(path.c_str(), RTLD_NOW);
 }
 
 SharedLibrary::~SharedLibrary() {
     if (mLibHandle != NULL) {
-        android_unload_sphal_library(mLibHandle);
+        dlclose(mLibHandle);
         mLibHandle = NULL;
     }
 }

cas/aidl/default/manifest.json

@@ -1,9 +1,8 @@
 {
     "name": "com.android.hardware.cas",
     "version": 1,
-    // For CAS HAL to open plugins from /vendor/lib, "vendor" namespace should be imported.
-    // ":sphal" is an alias for the "vendor" namespace in Vendor APEX.
+    // For CAS HAL to open plugins from /vendor/lib/mediacas
     "requireNativeLibs": [
-        ":sphal"
+        ":mediacas"
     ]
 }