Remove ACgroupController_getFlags to fix API breakage

Since ACgroupController_getFlags was introduced after LLNDK freeze it
causes media crashes due to missing symbol. Remove the new function and
re-implement cgroup controller detection to not require flags field but
instead check for its existence on the first access.

Bug: 135049992
Test: libcutils_test with and without CONFIG_CPUSETS enabled
Change-Id: I0220d6a926884dc22a7424d7d0a980c379c6f4eb
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
diff --git a/libprocessgroup/cgroup_map.cpp b/libprocessgroup/cgroup_map.cpp
index 92fcd1e..9797d76 100644
--- a/libprocessgroup/cgroup_map.cpp
+++ b/libprocessgroup/cgroup_map.cpp
@@ -70,8 +70,8 @@
 bool CgroupController::IsUsable() const {
     if (!HasValue()) return false;
 
-    uint32_t flags = ACgroupController_getFlags(controller_);
-    return (flags & CGROUPRC_CONTROLLER_FLAG_MOUNTED) != 0;
+    static bool enabled = (access(GetProcsFilePath("", 0, 0).c_str(), F_OK) == 0);
+    return enabled;
 }
 
 std::string CgroupController::GetTasksFilePath(const std::string& rel_path) const {
@@ -160,7 +160,6 @@
         const ACgroupController* controller = ACgroupFile_getController(i);
         LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
                   << ACgroupController_getVersion(controller) << " path "
-                  << ACgroupController_getFlags(controller) << " flags "
                   << ACgroupController_getPath(controller);
     }
 }