MediaUtils: Use delayed / lazy library loading

Postpone loading libutilscallstack until needed
to save memory.

Test: atest library_tests
Test: adb shell 'showmap $(pgrep mediametrics)'
Bug: 227536784
Change-Id: I3d4c9e9b6d854b013185e18fc20d4bec320df14e
diff --git a/media/utils/MediaUtilsDelayedLibrary.cpp b/media/utils/MediaUtilsDelayedLibrary.cpp
new file mode 100644
index 0000000..9054c1a
--- /dev/null
+++ b/media/utils/MediaUtilsDelayedLibrary.cpp
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "MediaUtilsDelayedLibrary.h"
+#include <utils/CallStack.h>
+
+// Methods that are dynamically linked.
+namespace {
+
+std::string getCallStackStringForTid(pid_t tid) {
+    android::CallStack cs{};
+    cs.update(0 /* ignoreDepth */, tid);
+    return cs.toString().c_str();
+}
+
+} // namespace
+
+// leave global, this is picked up from dynamic linking
+android::mediautils::delayed_library::DelayedDispatchTable gDelayedDispatchTable {
+    getCallStackStringForTid,
+};