Add 'depfile' option to actions.

pylib/gyp/generator/ninja.py

Index: pylib/gyp/generator/ninja.py
diff --git a/pylib/gyp/generator/ninja.py b/pylib/gyp/generator/ninja.py
index 5cda5c3ce1eb3af06375ae98e733b8600425a1af..0c7ce547c8862082cb0b0a07c4bdad3e04a294c6 100644
--- a/pylib/gyp/generator/ninja.py
+++ b/pylib/gyp/generator/ninja.py
@@ -599,9 +599,13 @@ class NinjaWriter(object):
       is_cygwin = (self.msvs_settings.IsRuleRunUnderCygwin(action)
                    if self.flavor == 'win' else False)
       args = action['action']
+      depfile = action.get('depfile', None)
+      if depfile:
+        depfile = self.ExpandSpecial(depfile, self.base_to_build)
       pool = 'console' if int(action.get('ninja_use_console', 0)) else None
       rule_name, _ = self.WriteNewNinjaRule(name, args, description,
-                                            is_cygwin, env, pool)
+                                            is_cygwin, env, pool,
+                                            depfile=depfile)
 
       inputs = [self.GypPathToNinja(i, env) for i in action['inputs']]
       if int(action.get('process_outputs_as_sources', False)):
@@ -1506,7 +1510,8 @@ class NinjaWriter(object):
       values = []
     ninja_file.variable(var, ' '.join(values))
 
-  def WriteNewNinjaRule(self, name, args, description, is_cygwin, env, pool):
+  def WriteNewNinjaRule(self, name, args, description, is_cygwin, env, pool,
+                        depfile=None):
     """Write out a new ninja "rule" statement for a given command.
 
     Returns the name of the new rule, and a copy of |args| with variables
@@ -1564,7 +1569,8 @@ class NinjaWriter(object):
     # GYP rules/actions express being no-ops by not touching their outputs.
     # Avoid executing downstream dependencies in this case by specifying
     # restat=1 to ninja.
-    self.ninja.rule(rule_name, command, description, restat=True, pool=pool,
+    self.ninja.rule(rule_name, command, description, depfile=depfile,
+                    restat=True, pool=pool,
                     rspfile=rspfile, rspfile_content=rspfile_content)
     self.ninja.newline()