Remove checked-in generated files and use build-time gen ones

Pre-requisite step for http://go/perfetto-libprotobuf
(get rid of libprotobuf runtime dependency).
This change keeps some checked-in headers as proxy shims
(e.g. include/core/data_source_config.h has only
#include ".../data_source_config.gen.h")
This is to handle potential reverts of the chromium roll
more easily. They will be removed in a follow-up.

Bug: 132880619
Test: CI
Change-Id: I2d8c391b060dac37209a640e269e13ae34e8981f
diff --git a/src/protozero/protoc_plugin/BUILD.gn b/src/protozero/protoc_plugin/BUILD.gn
index ab8f9a7..4a9c7f4 100644
--- a/src/protozero/protoc_plugin/BUILD.gn
+++ b/src/protozero/protoc_plugin/BUILD.gn
@@ -30,9 +30,9 @@
 # The plugin that generates standalone C++ objects from protos (xxx.gen.h).
 # This is used for core classes traced needs to know about such as
 # DataSourceDescriptor.
-perfetto_host_executable("cpp_obj_plugin") {
+perfetto_host_executable("cppgen_plugin") {
   sources = [
-    "cpp_obj_plugin.cc",
+    "cppgen_plugin.cc",
   ]
   deps = [
     "../../../gn:default_deps",