graphics_WebGLConformance: use tarballs for WebGLConformance test

client/site_tests/graphics_WebGLConformance/graphics_WebGLConformance.py

Index: client/site_tests/graphics_WebGLConformance/graphics_WebGLConformance.py
diff --git a/client/site_tests/graphics_WebGLConformance/graphics_WebGLConformance.py b/client/site_tests/graphics_WebGLConformance/graphics_WebGLConformance.py
index d07fb219917993ce1fb787deb5fc837b2f0b0ad9..b06cc70df7f31c7ede6ca0d05c639ebcc96d2a68 100644
--- a/client/site_tests/graphics_WebGLConformance/graphics_WebGLConformance.py
+++ b/client/site_tests/graphics_WebGLConformance/graphics_WebGLConformance.py
@@ -18,8 +18,18 @@ class graphics_WebGLConformance(site_ui_test.UITest):
         site_ui_test.UITest.initialize(self, creds)
 
 
-    def setup(self):
+    def setup(self, tarball='webgl-tests-0.0.1.tar.bz2'):
         shutil.rmtree(self.srcdir, ignore_errors=True)
+
+        dst_path = os.path.join(self.bindir, 'WebGL')
+        tarball_path = os.path.join(self.bindir, tarball)
+        if not os.path.exists(dst_path):
+            if not os.path.exists(tarball_path):
+                utils.get_file(
+                    'http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles/' + tarball,
+                     tarball_path)
+            utils.extract_tarball_to_dir(tarball_path, dst_path)
+
         shutil.copytree(os.path.join(self.bindir, 'WebGL'), self.srcdir)
         os.chdir(self.srcdir)
         utils.system('patch -p1 < ../r11002.patch')