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/traced/probes/probes_producer.cc b/src/traced/probes/probes_producer.cc
index 87e688d..9e4596c 100644
--- a/src/traced/probes/probes_producer.cc
+++ b/src/traced/probes/probes_producer.cc
@@ -24,14 +24,14 @@
 #include <string>
 
 #include "perfetto/base/logging.h"
-#include "perfetto/base/utils.h"
-#include "perfetto/base/weak_ptr.h"
-#include "perfetto/traced/traced.h"
-#include "perfetto/tracing/core/data_source_config.h"
-#include "perfetto/tracing/core/data_source_descriptor.h"
-#include "perfetto/tracing/core/trace_config.h"
-#include "perfetto/tracing/core/trace_packet.h"
-#include "perfetto/tracing/ipc/producer_ipc_client.h"
+#include "perfetto/ext/base/utils.h"
+#include "perfetto/ext/base/weak_ptr.h"
+#include "perfetto/ext/traced/traced.h"
+#include "perfetto/ext/tracing/core/data_source_config.h"
+#include "perfetto/ext/tracing/core/data_source_descriptor.h"
+#include "perfetto/ext/tracing/core/trace_config.h"
+#include "perfetto/ext/tracing/core/trace_packet.h"
+#include "perfetto/ext/tracing/ipc/producer_ipc_client.h"
 #include "src/traced/probes/android_log/android_log_data_source.h"
 #include "src/traced/probes/filesystem/inode_file_data_source.h"
 #include "src/traced/probes/ftrace/ftrace_config.h"