Reshuffle include/ directory layout

This CL reorganizes the include/ directory as follows:
1. The immediate subdirectories of include/ are now the stable API
   surface exposed to all embedders, with the exception of ext/.
2. ext/ contains the unstable API surface that is exposed only to chrome.

Test: builds on all configurations and passes tests
Bug: 132678367
Change-Id: If638d4b4c150fd591cd1db851283b25ff6083ed6
diff --git a/src/profiling/memory/client.h b/src/profiling/memory/client.h
index 72b9c6c..5b4a95e 100644
--- a/src/profiling/memory/client.h
+++ b/src/profiling/memory/client.h
@@ -25,7 +25,7 @@
 #include <mutex>
 #include <vector>
 
-#include "perfetto/base/unix_socket.h"
+#include "perfetto/ext/base/unix_socket.h"
 #include "src/profiling/memory/sampler.h"
 #include "src/profiling/memory/shared_ring_buffer.h"
 #include "src/profiling/memory/unhooked_allocator.h"