Fix canonicalize().

sdk/lib/_internal/pub/lib/src/path_source.dart

Index: sdk/lib/_internal/pub/lib/src/path_source.dart
diff --git a/sdk/lib/_internal/pub/lib/src/path_source.dart b/sdk/lib/_internal/pub/lib/src/path_source.dart
index ac37ec72224a7fdba057ef69425ff61c7d45b6c0..2b66e3b6b5b228d3cf3335b52205d273dcd5238e 100644
--- a/sdk/lib/_internal/pub/lib/src/path_source.dart
+++ b/sdk/lib/_internal/pub/lib/src/path_source.dart
@@ -32,18 +32,10 @@ class PathSource extends Source {
   }
 
   bool descriptionsEqual(description1, description2) {
-    try {
-      // Compare real paths after normalizing and resolving symlinks.
-      var path1 = canonicalize(description1["path"]);
-      var path2 = canonicalize(description2["path"]);
-      return path1 == path2;
-    } on FileIOException catch (ex) {
-      // If either of the files couldn't be found, fall back to just comparing
-      // the normalized paths.
-      var path1 = path.normalize(path.absolute(description1["path"]));
-      var path2 = path.normalize(path.absolute(description2["path"]));
-      return path1 == path2;
-    }
+    // Compare real paths after normalizing and resolving symlinks.
+    var path1 = canonicalize(description1["path"]);
+    var path2 = canonicalize(description2["path"]);
+    return path1 == path2;
   }
 
   Future<bool> install(PackageId id, String destination) {