Enable CurlClient tests on Windows by bundling curl.exe.

utils/pub/io.dart

Index: utils/pub/io.dart
diff --git a/utils/pub/io.dart b/utils/pub/io.dart
index 3bd88c404df8614f09b529c489b67bdf280df97d..e9c335c716a6bb9f0b1aafc96e3616505246b003 100644
--- a/utils/pub/io.dart
+++ b/utils/pub/io.dart
@@ -365,6 +365,13 @@ String getFullPath(entry) {
       .toNativePath();
 }
 
+/// Resolves [path] relative to the location of pub.dart.
+String relativeToPub(String path) {
+  var scriptPath = new File(new Options().script).fullPathSync();
+  var scriptDir = new Path.fromNative(scriptPath).directoryPath;
+  return scriptDir.append(path).canonicalize().toNativePath();
+}
+
 // TODO(nweiz): make this configurable
 /**
  * The amount of time in milliseconds to allow HTTP requests before assuming
@@ -646,14 +653,10 @@ Future<bool> _extractTarGzWindows(InputStream stream, String destination) {
   // read from stdin instead of a file. Consider resurrecting that version if
   // we can figure out why it fails.
 
-  // Find 7zip.
-  var scriptPath = new File(new Options().script).fullPathSync();
-  var scriptDir = new Path.fromNative(scriptPath).directoryPath;
-
   // Note: This line of code gets munged by create_sdk.py to be the correct
   // relative path to 7zip in the SDK.
   var pathTo7zip = '../../third_party/7zip/7za.exe';
-  var command = scriptDir.append(pathTo7zip).canonicalize().toNativePath();
+  var command = relativeToPub(pathTo7zip);
 
   var tempDir;