Import //fetch from Web Platform Tests.

third_party/WebKit/LayoutTests/external/wpt/fetch/api/resources/cache.py

Index: third_party/WebKit/LayoutTests/external/wpt/fetch/api/resources/cache.py
diff --git a/third_party/WebKit/LayoutTests/external/wpt/fetch/api/resources/cache.py b/third_party/WebKit/LayoutTests/external/wpt/fetch/api/resources/cache.py
new file mode 100644
index 0000000000000000000000000000000000000000..899638716a100a66c06cebbf92c31de7c705498b
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/external/wpt/fetch/api/resources/cache.py
@@ -0,0 +1,18 @@
+ETAG = '"123abc"'
+CONTENT_TYPE = "text/plain"
+CONTENT = "lorem ipsum dolor sit amet"
+
+
+def main(request, response):
+    # let caching kick in if possible (conditional GET)
+    etag = request.headers.get("If-None-Match", None)
+    if etag == ETAG:
+        response.headers.set("X-HTTP-STATUS", 304)
+        response.status = (304, "Not Modified")
+        return ""
+
+    # cache miss, so respond with the actual content
+    response.status = (200, "OK")
+    response.headers.set("ETag", ETAG)
+    response.headers.set("Content-Type", CONTENT_TYPE)
+    return CONTENT