Allow for GN Grit targets to depend on a stamp file instead of the first output in the .grd file.

build/secondary/tools/grit/grit_rule.gni

 # Copyright 2014 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.
 
 # Instantiate grit. This will produce a script target to run grit, and a
 # static library that compiles the .cc files.
 #
 # Parameters
 #
 #   source (required)
@@ skipping 346 matching lines @@
         !invoker.use_qualified_include) {
       include_dirs = [ output_dir ]
     }
     visibility = target_visibility
   }
 
   grit_custom_target = target_name + "_grit"
   action(grit_custom_target) {
     script = "//tools/grit/grit.py"
     inputs = grit_inputs
-    outputs = grit_outputs
-    depfile = "$output_dir/${grit_output_name}.d"
+    depend_on_stamp =

[cjhopman, 2015/03/14 00:37:45]

Do we need to support not depending on a stamp?

[knn, 2015/03/16 10:53:42]

This only so that the build does not break due to an unrecognized flag. Added a
TODO to remove.

[cjhopman, 2015/03/16 20:13:46]

But, we can't set depend_on_stamp for any target until grit is rolled anyway,
right?

+        defined(invoker.depend_on_stamp) && invoker.depend_on_stamp
+    if (depend_on_stamp) {
+      # Need this for migrating existing targets without clobbering.
+      depfile = "$output_dir/${grit_output_name}_stamp.d"
+      outputs = [
+        "${depfile}.stamp",
+      ]
+    } else {
+      depfile = "$output_dir/${grit_output_name}.d"
+      outputs = []
+    }
+    outputs += grit_outputs
 
     args = [
       "-i",
       source_path,
       "build",
     ]
     if (resource_ids != "") {
       args += [
         "-f",
         resource_ids,
       ]
     }
     args += [
-              "-o",
-              rebased_output_dir,
-              "--depdir",
-              ".",
-              "--depfile",
-              rebase_path(depfile, root_build_dir),
-              "--write-only-new=1",
-            ] + grit_defines
+      "-o",
+      rebased_output_dir,
+      "--depdir",
+      ".",
+      "--depfile",
+      rebase_path(depfile, root_build_dir),
+      "--write-only-new=1",
+    ]
+    if (depend_on_stamp) {
+      args += [ "--depend-on-stamp" ]
+    }
+    args += grit_defines
 
     # Add extra defines with -D flags.
     if (defined(invoker.defines)) {
       foreach(i, invoker.defines) {
         args += [
           "-D",
           i,
         ]
       }
     }
@@ skipping 43 matching lines @@
     if (defined(invoker.configs)) {
       configs += invoker.configs
     }
 
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
     output_name = grit_output_name
   }
 }