Add BufferClient information to dumpsys

Now "adb shell dumpsys bufferhubd" will tell you how many buffers have
been allocated via the binder service as well.

The reason for not having buffer info is because the info should be
stored with BufferNode, which is yet another pending CL. After
b/117790952 is resolved we can print them.

Test: run "adb shell dumpsys bufferhubd" after "atest
buffer_hub_binder_service-test" should print "Active BufferClients: 1"
Bug: 116526156

Change-Id: I72df3a2d4795bdba0ddf42c1a27a74cd5987f3d8
diff --git a/services/vr/bufferhubd/buffer_hub_binder.cpp b/services/vr/bufferhubd/buffer_hub_binder.cpp
index 7da1532..017a2ab 100644
--- a/services/vr/bufferhubd/buffer_hub_binder.cpp
+++ b/services/vr/bufferhubd/buffer_hub_binder.cpp
@@ -46,8 +46,14 @@
             "Input arguments are ignored.\n");
   }
 
-  // TODO(b/116526156): output real data in this class once we have it
+  fprintf(out, "Binder service:\n");
+  // Active buffers
+  fprintf(out, "Active BufferClients: %zu\n", client_list_.size());
+  // TODO(b/117790952): print buffer information after BufferNode has it
+  // TODO(b/116526156): print more information once we have them
+
   if (pdx_service_) {
+    fprintf(out, "\nPDX service:\n");
     // BufferHubService::Dumpstate(size_t) is not actually using the param
     // So just using 0 as the length
     fprintf(out, "%s", pdx_service_->DumpState(0).c_str());