🚙 GN: Add write_runtime_deps variable

tools/gn/variables.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/variables.h"
 
 namespace variables {
 
 // Built-in variables ----------------------------------------------------------
 
@@ skipping 1498 matching lines @@
     "  Any target in \"//bar/\" or any subdirectory thereof:\n"
     "    visibility = [ \"//bar/*\" ]\n"
     "\n"
     "  Just these specific targets:\n"
     "    visibility = [ \":mything\", \"//foo:something_else\" ]\n"
     "\n"
     "  Any target in the current directory and any subdirectory thereof, plus\n"
     "  any targets in \"//bar/\" and any subdirectory thereof.\n"
     "    visibility = [ \"./*\", \"//bar/*\" ]\n";
 
+const char kWriteRuntimeDeps[] = "write_runtime_deps";
+const char kWriteRuntimeDeps_HelpShort[] =
+    "write_runtime_deps: Writes the target's runtime_deps to the given path.";
+const char kWriteRuntimeDeps_Help[] =
+    "write_runtime_deps: Writes the target's runtime_deps to the given path.\n"
+    "\n"
+    "  Does not synchronously write the file, but rather schedules it\n"
+    "  to be written at the end of generation.\n"
+    "\n"
+    "  If the file exists and the contents are identical to that being\n"
+    "  written, the file will not be updated. This will prevent unnecessary\n"
+    "  rebuilds of targets that depend on this file.\n"
+    "\n"
+    "  Path must be within the output directory.\n";

[brettw, 2016/03/28 23:06:35]

Can you add here:

See "gn help runtime_deps" for how the runtime dependencies are computed. 

The format of this file will list one file per line with no escaping. The files
will be relative to the root_build_dir. The first line of the file will be the
main output file of the target itself. The file contents will be the same as
requesting the runtime deps be written on the command line (see "gn help
--runtime-deps-list-file").

[agrieve, 2016/03/29 16:14:01]

Done.

+
 // -----------------------------------------------------------------------------
 
 VariableInfo::VariableInfo()
     : help_short(""),
       help("") {
 }
 
 VariableInfo::VariableInfo(const char* in_help_short, const char* in_help)
     : help_short(in_help_short),
       help(in_help) {
@@ skipping 60 matching lines @@
     INSERT_VARIABLE(PrecompiledHeader)
     INSERT_VARIABLE(PrecompiledSource)
     INSERT_VARIABLE(Public)
     INSERT_VARIABLE(PublicConfigs)
     INSERT_VARIABLE(PublicDeps)
     INSERT_VARIABLE(ResponseFileContents)
     INSERT_VARIABLE(Script)
     INSERT_VARIABLE(Sources)
     INSERT_VARIABLE(Testonly)
     INSERT_VARIABLE(Visibility)
+    INSERT_VARIABLE(WriteRuntimeDeps)
   }
   return info_map;
 }
 
 #undef INSERT_VARIABLE
 
 }  // namespace variables