Download the chromedriver version based on the chrome version (dart-lang/sse#9)

* Download the chromedriver version based on the chrome version

* fix webdriver

pkgs/sse/.travis.yml

diff --git a/pkgs/sse/.travis.yml b/pkgs/sse/.travis.yml
index 36eb960..3756641 100644
--- a/pkgs/sse/.travis.yml
+++ b/pkgs/sse/.travis.yml
@@ -26,7 +26,9 @@
   - sh -e /etc/init.d/xvfb start
 
 before_script:
-  - wget http://chromedriver.storage.googleapis.com/2.46/chromedriver_linux64.zip
+  - "export CHROME_LATEST_VERSION=$(/usr/bin/google-chrome --version | cut -d' ' -f3 | cut -d'.' -f1)"
+  - "export CHROME_DRIVER_VERSION=$(wget -qO- https://chromedriver.storage.googleapis.com/LATEST_RELEASE_$CHROME_LATEST_VERSION)"
+  - "wget https://chromedriver.storage.googleapis.com/$CHROME_DRIVER_VERSION/chromedriver_linux64.zip"
   - unzip chromedriver_linux64.zip
   - export PATH=$PATH:$PWD
   - ./tool/travis-setup.sh

pkgs/sse/pubspec.yaml

diff --git a/pkgs/sse/pubspec.yaml b/pkgs/sse/pubspec.yaml
index fd170d7..923326e 100644
--- a/pkgs/sse/pubspec.yaml
+++ b/pkgs/sse/pubspec.yaml
@@ -22,4 +22,4 @@
 dev_dependencies:
   shelf_static: ^0.2.8
   test: ^1.5.3
-  webdriver: ^2.0.0
+  webdriver: ^2.1.0

pkgs/sse/test/sse_test.dart

diff --git a/pkgs/sse/test/sse_test.dart b/pkgs/sse/test/sse_test.dart
index 636bab9..62fe4c6 100644
--- a/pkgs/sse/test/sse_test.dart
+++ b/pkgs/sse/test/sse_test.dart
@@ -41,11 +41,13 @@
             listDirectories: true, defaultDocument: 'index.html'));
 
     server = await io.serve(cascade.handler, 'localhost', 0);
-    webdriver = await createDriver(desired: {
-      'chromeOptions': {
-        'args': ['--headless']
-      }
-    });
+    var capabilities = Capabilities.chrome
+      ..addAll({
+        Capabilities.chromeOptions: {
+          'args': ['--headless']
+        }
+      });
+    webdriver = await createDriver(desired: capabilities);
   });
 
   tearDown(() async {