Revert 214325 "Revert 214254 "Add initial prototype for the GN m..."

The issue was already fixed :)

> Revert 214254 "Add initial prototype for the GN meta-buildsystem."
>
> It broke the check_licenses step on Android (see http://build.chromium.org/p/chromium.linux/builders/Android%20Builder%20%28dbg%29/builds/39904/steps/check_licenses/logs/stdio):
>
> @@@BUILD_STEP check_licenses@@@
> > /b/build/slave/Android_Builder__dbg_/build/src/android_webview/tools/webview_licenses.py scan
> Got LicenseError "missing README.chromium or licenses.py SPECIAL_CASES entry" while scanning tools/gn/secondary/base/third_party/dynamic_annotations
> Got LicenseError "missing README.chromium or licenses.py SPECIAL_CASES entry" while scanning tools/gn/secondary/third_party/modp_b64
> < /b/build/slave/Android_Builder__dbg_/build/src/android_webview/tools/webview_licenses.py scan
> ERROR: process exited with code 2
> @@@STEP_FAILURE@@@
>
>
> > Add initial prototype for the GN meta-buildsystem.
> >
> > This is currently not hooked into the build. To build, add a reference to the
> > gn.gyp file to build/all.gyp
> >
> > R=darin@chromium.org, scottmg@chromium.org
> >
> > Review URL: https://codereview.chromium.org/21114002
>
> TBR=brettw@chromium.org
>
> Review URL: https://codereview.chromium.org/21084010

TBR=bauerb@chromium.org

Review URL: https://codereview.chromium.org/21204003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@214333 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 71 insertions, 0 deletions

diff --git a/tools/gn/ninja_helper.h b/tools/gn/ninja_helper.h
new file mode 100644
index 0000000..5bea29e
--- /dev/null
+++ b/tools/gn/ninja_helper.h
@@ -0,0 +1,71 @@
+// 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.
+
+#ifndef TOOLS_GN_NINJA_HELPER_H_
+#define TOOLS_GN_NINJA_HELPER_H_
+
+#include <iosfwd>
+#include <string>
+
+#include "tools/gn/filesystem_utils.h"
+#include "tools/gn/output_file.h"
+
+class BuildSettings;
+class SourceDir;
+class SourceFile;
+class Target;
+
+// NinjaHelper -----------------------------------------------------------------
+
+class NinjaHelper {
+ public:
+  NinjaHelper(const BuildSettings* build_settings);
+  ~NinjaHelper();
+
+  // Ends in a slash.
+  std::string GetTopleveOutputDir() const;
+
+  // Ends in a slash.
+  std::string GetTargetOutputDir(const Target* target) const;
+
+  // Example: "base/base.ninja". The string version will not be escaped, and
+  // will always have slashes for path separators.
+  OutputFile GetNinjaFileForTarget(const Target* target) const;
+
+  // Returns the name of the root .ninja file for the given toolchain.
+  OutputFile GetNinjaFileForToolchain(const Settings* settings) const;
+
+  // Given a source file relative to the source root, returns the output
+  // filename.
+  OutputFile GetOutputFileForSource(const Target* target,
+                                   const SourceFile& source,
+                                   SourceFileType type) const;
+
+  // Returns the filename produced by the given output.
+  //
+  // Some targets make multiple files (like a .dll and an import library). This
+  // function returns the name of the file other targets should depend on and
+  // link to (so in this example, the import library).
+  OutputFile GetTargetOutputFile(const Target* target) const;
+
+  // Returns the relative directory in either slashes or the system separator
+  // from the ninja directory (e.g. "out/Debug") to the source root (e.g.
+  // "../.."). It has no terminating slash.
+  const std::string& build_to_src_no_last_slash() const {
+    return build_to_src_no_last_slash_;
+  }
+  const std::string& build_to_src_system_no_last_slash() const {
+    return build_to_src_system_no_last_slash_;
+  }
+
+ private:
+  const BuildSettings* build_settings_;
+
+  std::string build_to_src_no_last_slash_;
+  std::string build_to_src_system_no_last_slash_;
+
+  DISALLOW_COPY_AND_ASSIGN(NinjaHelper);
+};
+
+#endif  // TOOLS_GN_NINJA_HELPER_H_