Add optional public header checking to GN build

tools/gn/trace.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/trace.h"
 
 #include <algorithm>
 #include <map>
 #include <sstream>
 #include <vector>
@@ skipping 167 matching lines @@
 std::string SummarizeTraces() {
   if (!trace_log)
     return std::string();
 
   std::vector<TraceItem*> events = trace_log->events();
 
   // Classify all events.
   std::vector<const TraceItem*> parses;
   std::vector<const TraceItem*> file_execs;
   std::vector<const TraceItem*> script_execs;
+  std::vector<const TraceItem*> check_headers;
+  int headers_checked = 0;
   for (size_t i = 0; i < events.size(); i++) {
     switch (events[i]->type()) {
       case TraceItem::TRACE_FILE_PARSE:
         parses.push_back(events[i]);
         break;
       case TraceItem::TRACE_FILE_EXECUTE:
         file_execs.push_back(events[i]);
         break;
       case TraceItem::TRACE_SCRIPT_EXECUTE:
         script_execs.push_back(events[i]);
         break;
+      case TraceItem::TRACE_CHECK_HEADERS:
+        check_headers.push_back(events[i]);
+        break;
+      case TraceItem::TRACE_CHECK_HEADER:
+        headers_checked++;
+        break;
       case TraceItem::TRACE_FILE_LOAD:
       case TraceItem::TRACE_FILE_WRITE:
       case TraceItem::TRACE_DEFINE_TARGET:
         break;  // Ignore these for the summary.
     }
   }
 
   std::ostringstream out;
   SummarizeParses(parses, out);
   out << std::endl;
   SummarizeFileExecs(file_execs, out);
   out << std::endl;
   SummarizeScriptExecs(script_execs, out);
   out << std::endl;
 
+  // Generally there will only be one header check, but it's theoretically
+  // possible for more than one to run if more than one build is going in
+  // parallel. Just report the total of all of them.
+  if (!check_headers.empty()) {
+    float check_headers_time = 0;
+    for (size_t i = 0; i < check_headers.size(); i++)
+      check_headers_time += check_headers[i]->delta().InMillisecondsF();
+
+    out << "Header check time: (total time in ms, files checked)\n";
+    out << base::StringPrintf(" %8.2f  %d\n",
+                              check_headers_time, headers_checked);
+  }
+
   return out.str();
 }
 
 void SaveTraces(const base::FilePath& file_name) {
   std::ostringstream out;
 
   out << "{\"traceEvents\":[";
 
   std::string quote_buffer;  // Allocate outside loop to prevent reallocationg.
 
@@ skipping 30 matching lines @@
         out << "\"file_exec\"";
         break;
       case TraceItem::TRACE_FILE_WRITE:
         out << "\"file_write\"";
         break;
       case TraceItem::TRACE_SCRIPT_EXECUTE:
         out << "\"script_exec\"";
         break;
       case TraceItem::TRACE_DEFINE_TARGET:
         out << "\"define\"";
+        break;
+      case TraceItem::TRACE_CHECK_HEADER:
+        out << "\"hdr\"";
+        break;
+      case TraceItem::TRACE_CHECK_HEADERS:
+        out << "\"header_check\"";
+        break;
     }
 
     if (!item.toolchain().empty() || !item.cmdline().empty()) {
       out << ",\"args\":{";
       bool needs_comma = false;
       if (!item.toolchain().empty()) {
         quote_buffer.resize(0);
         base::EscapeJSONString(item.toolchain(), true, &quote_buffer);
         out << "\"toolchain\":" << quote_buffer;
         needs_comma = true;
@@ skipping 10 matching lines @@
     }
     out << "}";
   }
 
   out << "]}";
 
   std::string out_str = out.str();
   base::WriteFile(file_name, out_str.data(),
                        static_cast<int>(out_str.size()));
 }