Use helper methods for running pub.

sdk/lib/_internal/pub/lib/src/solver/version_solver.dart

Index: sdk/lib/_internal/pub/lib/src/solver/version_solver.dart
diff --git a/sdk/lib/_internal/pub/lib/src/solver/version_solver.dart b/sdk/lib/_internal/pub/lib/src/solver/version_solver.dart
index 7b6713b0895f9af10a906cfeeb1470600ae12b4f..e2b7b5bf0598ec0f3eb66e57d91a428ec101b39d 100644
--- a/sdk/lib/_internal/pub/lib/src/solver/version_solver.dart
+++ b/sdk/lib/_internal/pub/lib/src/solver/version_solver.dart
@@ -176,29 +176,6 @@ abstract class SolveFailure implements ApplicationException {
   SolveFailure(this.package, Iterable<Dependency> dependencies)
       : dependencies = dependencies != null ? dependencies : <Dependency>[];
 
-  /// Writes [dependencies] to [buffer] as a bullet list. If [describe] is
-  /// passed, it will be called for each dependency and the result will be
-  /// written next to the dependency.
-  void writeDependencies(StringBuffer buffer,
-      [String describe(PackageDep dep)]) {
-    var map = {};
-    for (var dep in dependencies) {
-      map[dep.depender] = dep.dep;
-    }
-
-    var names = map.keys.toList();
-    names.sort();
-
-    for (var name in names) {
-      buffer.writeln("- '$name' ");
-      if (describe != null) {
-        buffer.writeln(describe(map[name]));
-      } else {
-        buffer.writeln("depends on version ${map[name].constraint}");
-      }
-    }
-  }
-
   String toString() {
     if (dependencies.isEmpty) return _message;
 
@@ -213,9 +190,8 @@ abstract class SolveFailure implements ApplicationException {
     var names = map.keys.toList();
     names.sort();
 
-    for (var name in names) {
-      buffer.writeln("- '$name' ${_describeDependency(map[name])}");
-    }
+    buffer.writeAll(names.map(
+        (name) => "- '$name' ${_describeDependency(map[name])}"), '\n');
 
     return buffer.toString();
   }