Add toUri and fromUri functions to pathos.

utils/apidoc/apidoc.dart

Index: utils/apidoc/apidoc.dart
diff --git a/utils/apidoc/apidoc.dart b/utils/apidoc/apidoc.dart
index ef6bae54202583ff08ceee57b6f602620740bff7..74a798e844c6bf5f62609b79ed8a24fd9b08be63 100644
--- a/utils/apidoc/apidoc.dart
+++ b/utils/apidoc/apidoc.dart
@@ -148,7 +148,7 @@ void main() {
       }
 
       if (new File.fromPath(libPath).existsSync()) {
-        apidocLibraries.add(_pathToFileUri(libPath.toNativePath()));
+        apidocLibraries.add(pathos.toUri(libPath.toNativePath()));
         includedLibraries.add(libName);
       } else {
         print('Warning: could not find package at $path');
@@ -162,7 +162,7 @@ void main() {
     for (var lib in extraLibraries) {
       var libPath = new Path('../../$lib');
       if (new File.fromPath(libPath).existsSync()) {
-        apidocLibraries.add(_pathToFileUri(libPath.toNativePath()));
+        apidocLibraries.add(pathos.toUri(libPath.toNativePath()));
         var libName = libPath.filename.replaceAll('.dart', '');
         includedLibraries.add(libName);
       }
@@ -481,13 +481,3 @@ class Apidoc extends Dartdoc {
   }
 }
 
-/** Converts a local path string to a `file:` [Uri]. */
-Uri _pathToFileUri(String path) {
-  path = pathos.absolute(path);
-  if (Platform.operatingSystem != 'windows') {
-    return Uri.parse('file://$path');
-  } else {
-    return Uri.parse('file:///${path.replaceAll("\\", "/")}');
-  }
-}
-