Work on GN iOS build.

tools/gn/gyp_target_writer.h

 // 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_GYP_TARGET_WRITER_H_
 #define TOOLS_GN_GYP_TARGET_WRITER_H_
 
 #include <iosfwd>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "tools/gn/gyp_helper.h"
 #include "tools/gn/path_output.h"
 
 class BuilderRecord;
 class Err;
 class Settings;
 class SourceFile;
 class Target;
 class Toolchain;
 
 class GypTargetWriter {
  public:
   struct TargetGroup {
-    TargetGroup()
-        : debug(NULL),
-          release(NULL),
-          host_debug(NULL),
-          host_release(NULL),
-          debug64(NULL),
-          release64(NULL) {
+    TargetGroup();
+
+    // Returns "a" record associated with this group. This is used when getting
+    // general things like the sources list that should be the same across all
+    // records in a group.
+    const BuilderRecord* get() const {
+      // We assume we always have either a host or a target debug build.
+      return debug ? debug : host_debug;
     }
+
     const BuilderRecord* debug;
     const BuilderRecord* release;
 
     // When the main compile is targeting a different architecture, these will
     // contain the builds with the host system's toolchain. Only supported on
     // Linux.
     const BuilderRecord* host_debug;
     const BuilderRecord* host_release;
 
     // On Windows, we do both 32-bit and 64-bit builds. Null on non-Windows.
     const BuilderRecord* debug64;
     const BuilderRecord* release64;
+
+    // On Mac/iOS, there are some nontrivial differences between the GYP Ninja
+    // build and the GYP XCode build. In GYP, these are parameterized as
+    // conditions using the generator flag. To emulate this, we have different
+    // builds for the XCode and Ninja versions of the GYP file, and the
+    // generator wraps everything in a big condition so that GYP does the right
+    // thing.
+    //
+    // These refer to the GYP-XCode build. The "regular" debug and release
+    // targets above refer to the GYP-Ninja build.
+    const BuilderRecord* xcode_debug;
+    const BuilderRecord* xcode_release;
+
+    // Optional host versions of the xcode config when cross-compiling to iOS.
+    const BuilderRecord* xcode_host_debug;
+    const BuilderRecord* xcode_host_release;
   };
 
   GypTargetWriter(const Target* target,
                   const Toolchain* toolchain,
                   const SourceDir& gyp_dir,
                   std::ostream& out);
   virtual ~GypTargetWriter();
 
   static void WriteFile(const SourceFile& gyp_file,
                         const std::vector<TargetGroup>& targets,
@@ skipping 16 matching lines @@
   std::ostream& out_;
 
   GypHelper helper_;
   PathOutput path_output_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GypTargetWriter);
 };
 
 #endif  // TOOLS_GN_GYP_TARGET_WRITER_H_