Pivot source files into top-level src,include and unify test target

See discussion in go/perfetto-build-files .
This is to disambiguate things like
  #include "base/logging.h"
when in the chrome tree.

Also this CL unifies the test targets into two monolithic targets:
perfetto_tests and perfetto_benchmarks. This is to avoid ending
up with confusing binary names in the chrome tree (e.g.,
ipc_unittests)

Bug: 68710794
Change-Id: I1768e15b661406052b2be060d7aab0f1e7443a98
diff --git a/BUILD.gn b/BUILD.gn
index 50df164..a9f9a35 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -18,9 +18,9 @@
   testonly = true  # allow to build also test targets
   deps = [
     ":tests",
-    "ftrace_reader:ftrace_reader_demo",
-    "ipc/src/protoc_plugin:ipc_plugin($host_toolchain)",
-    "protozero/src/protoc_plugin($host_toolchain)",
+    "src/ftrace_reader:ftrace_reader_demo",
+    "src/ipc/protoc_plugin:ipc_plugin($host_toolchain)",
+    "src/protozero/protoc_plugin($host_toolchain)",
     "tools/ftrace_proto_gen:ftrace_proto_gen",
   ]
 }
@@ -28,16 +28,16 @@
 group("tests") {
   testonly = true
   deps = [
-    "ftrace_reader:ftrace_reader_integrationtests",
-    "ftrace_reader:ftrace_reader_unittests",
-    "ipc:ipc_unittests",
-    "perfetto_base:perfetto_base_unittests",
-    "protozero:protozero_unittests",
+    "src/base:perfetto_base_unittests",
+    "src/ftrace_reader:ftrace_reader_integrationtests",
+    "src/ftrace_reader:ftrace_reader_unittests",
+    "src/ipc:perfetto_ipc_unittests",
+    "src/protozero:protozero_unittests",
+    "src/tracing:tracing_unittests",
     "tools/sanitizers_unittests",
-    "tracing:tracing_unittests",
   ]
 
   if (!build_with_chromium) {
-    deps += [ "tracing:tracing_benchmarks" ]
+    deps += [ "src/tracing:tracing_benchmarks" ]
   }
 }