trace_to_text: split out proto-full from proto-lite deps

This CL splits trace_to_text into separate translation units.
This makes the code a bit more readable by splitting the monster
main.cc and, more importantly, allows to isolate a subset of
trace_to_text which depends only on protobuf-lite and not on full.
This is to avoid pulling the whole protobuf-full in WASM and
avoid polluting the wasm and ui targets with testonly=true.

Bug: 117977226
Test: everything builds + unittests
Change-Id: I5285a0435e52e2742e97062fa13626adfe1fbcee

tools/trace_to_text/proto_full_utils.h

diff --git a/tools/trace_to_text/proto_full_utils.h b/tools/trace_to_text/proto_full_utils.h
new file mode 100644
index 0000000..65d7071
--- /dev/null
+++ b/tools/trace_to_text/proto_full_utils.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef TOOLS_TRACE_TO_TEXT_PROTO_FULL_UTILS_H_
+#define TOOLS_TRACE_TO_TEXT_PROTO_FULL_UTILS_H_
+
+// This file provides a wrapper around protobuf libraries that can be used only
+// when targeting libprotobuf-full.
+
+#include <google/protobuf/compiler/importer.h>
+#include <string>
+
+#include "perfetto/base/logging.h"
+
+namespace perfetto {
+namespace trace_to_text {
+
+class MultiFileErrorCollectorImpl
+    : public ::google::protobuf::compiler::MultiFileErrorCollector {
+ public:
+  ~MultiFileErrorCollectorImpl() override;
+  void AddError(const std::string& filename,
+                int line,
+                int column,
+                const std::string& message) override;
+
+  void AddWarning(const std::string& filename,
+                  int line,
+                  int column,
+                  const std::string& message) override;
+};
+
+}  // namespace trace_to_text
+}  // namespace perfetto
+
+#endif  // TOOLS_TRACE_TO_TEXT_PROTO_FULL_UTILS_H_