Add "bundle_data" target as first step for adding bundle support to gn.

tools/gn/target.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/target.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 204 matching lines @@
     case STATIC_LIBRARY:
       return "Static library";
     case SOURCE_SET:
       return "Source set";
     case COPY_FILES:
       return "Copy";
     case ACTION:
       return "Action";
     case ACTION_FOREACH:
       return "ActionForEach";
+    case BUNDLE_DATA:
+      return "Bundle data";
     default:
       return "";
   }
 }
 
 Target* Target::AsTarget() {
   return this;
 }
 
 const Target* Target::AsTarget() const {
@@ skipping 237 matching lines @@
     recursive_hard_deps_.insert(pair.ptr->recursive_hard_deps().begin(),
                                 pair.ptr->recursive_hard_deps().end());
   }
 }
 
 void Target::FillOutputFiles() {
   const Tool* tool = toolchain_->GetToolForTargetFinalOutput(this);
   bool check_tool_outputs = false;
   switch (output_type_) {
     case GROUP:
+    case BUNDLE_DATA:
     case SOURCE_SET:
     case COPY_FILES:
     case ACTION:
     case ACTION_FOREACH: {
       // These don't get linked to and use stamps which should be the first
       // entry in the outputs. These stamps are named
       // "<target_out_dir>/<targetname>.stamp".
       dependency_output_file_ = GetTargetOutputDirAsOutputFile(this);
       dependency_output_file_.value().append(GetComputedOutputName(true));
       dependency_output_file_.value().append(".stamp");
@@ skipping 225 matching lines @@
   if (!EnsureFileIsGeneratedByDependency(this, out_file, true, false,
                                          &seen_targets)) {
     // Check object files (much slower and very rare) only if the "normal"
     // output check failed.
     seen_targets.clear();
     if (!EnsureFileIsGeneratedByDependency(this, out_file, true, true,
                                            &seen_targets))
       g_scheduler->AddUnknownGeneratedInput(this, source);
   }
 }