Refactor the library tag handler to share code between standalone dart and the snapshot generator.

bin/dartutils.h

Index: bin/dartutils.h
===================================================================
--- bin/dartutils.h	(revision 1664)
+++ bin/dartutils.h	(working copy)
@@ -10,6 +10,51 @@
 
 #include "include/dart_api.h"
 
+class CommandLineOptions {
+ public:
+  explicit CommandLineOptions(int max_count)
+      : count_(0), max_count_(max_count), arguments_(NULL) {
+    static const int kWordSize = sizeof(intptr_t);
+    arguments_ = reinterpret_cast<const char **>(malloc(max_count * kWordSize));
+    if (arguments_ == NULL) {
+      max_count_ = 0;
+    }
+  }
+  ~CommandLineOptions() {
+    free(arguments_);
+    count_ = 0;
+    max_count_ = 0;
+    arguments_ = NULL;
+  }
+
+  int count() const { return count_; }
+  const char** arguments() const { return arguments_; }
+
+  const char* GetArgument(int index) const {
+    return (index >= 0 && index < count_) ? arguments_[index] : NULL;
+  }
+  void AddArgument(const char* argument) {
+    if (count_ < max_count_) {
+      arguments_[count_] = argument;
+      count_ += 1;
+    } else {
+      abort();  // We should never get into this situation.
+    }
+  }
+
+  void operator delete(void* pointer) { abort(); }
+
+ private:
+  void* operator new(size_t size);
+  CommandLineOptions(const CommandLineOptions&);
+  void operator=(const CommandLineOptions&);
+
+  int count_;
+  int max_count_;
+  const char** arguments_;
+};
+
+
 class DartUtils {
  public:
   static int64_t GetIntegerValue(Dart_Handle value_obj);
@@ -23,14 +68,29 @@
   static void SetStringInstanceField(Dart_Handle handle,
                                      const char* name,
                                      const char* val);
+  static bool IsDartSchemeURL(const char* url_name);
+  static Dart_Handle CanonicalizeURL(CommandLineOptions* url_mapping,
+                                     Dart_Handle library,
+                                     const char* url_str);
+  static Dart_Handle ReadStringFromFile(const char* filename);
+  static Dart_Handle LoadSource(CommandLineOptions* url_mapping,
+                                Dart_Handle library,
+                                Dart_Handle url,
+                                Dart_LibraryTag tag,
+                                const char* filename);
 
+  static const char* kDartScheme;
   static const char* kBuiltinLibURL;
   static const char* kCoreLibURL;
   static const char* kCoreImplLibURL;
   static const char* kCoreNativeWrappersLibURL;
 
   static const char* kIdFieldName;
+
  private:
+  static const char* GetCanonicalPath(const char* reference_dir,
+                                      const char* filename);
+
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(DartUtils);
 };