Add a wpt command for updating expectation metadata.

The |wpt update-expectations| command takes a list of raw log files,
and updates the expectation data located in the directory supplied
thorugh the --metadata keyword argument. This metadata is used by
subsequent test runs to determine the expected test results.

By default the "product" property is used as a possible conditional on
the data; this means that if multiple logs are passed in
simultaneously then different results will be distinguished by "if
product==foo" conditions in the metadata.

tools/wpt/commands.json

@@ -1,6 +1,10 @@
 {
     "run": {"path": "run.py", "script": "run", "parser": "create_parser", "help": "Run tests in a browser",
             "virtualenv": true, "install": ["requests"], "requirements": ["../wptrunner/requirements.txt"]},
+    "update-expectations": {"path": "update.py", "script": "update_expectations",
+                            "parser": "create_parser_update", "help": "Update expectations files from raw logs.",
+                            "virtualenv": true, "install": ["requests"],
+                            "requirements": ["../wptrunner/requirements.txt"]},
     "files-changed": {"path": "testfiles.py", "script": "run_changed_files", "parser": "get_parser",
                       "help": "Get a list of files that have changed", "virtualenv": false},
     "tests-affected": {"path": "testfiles.py", "script": "run_tests_affected", "parser": "get_parser_affected",

tools/wpt/update.py

@@ -0,0 +1,32 @@
+import os
+import sys
+
+wpt_root = os.path.abspath(os.path.join(os.path.dirname(__file__), os.pardir, os.pardir))
+sys.path.insert(0, os.path.abspath(os.path.join(wpt_root, "tools")))
+
+
+def create_parser_update():
+    from wptrunner import wptcommandline
+
+    return wptcommandline.create_parser_update()
+
+
+def update_expectations(venv, **kwargs):
+    from wptrunner import wptcommandline
+    from wptrunner.update import setup_logging, WPTUpdate
+
+    if not kwargs["tests_root"]:
+        kwargs["tests_root"] = wpt_root
+
+    if not kwargs["manifest_path"]:
+        kwargs["manifest_path"] = os.path.join(wpt_root, "MANIFEST.json")
+
+    if "product" not in kwargs["extra_property"]:
+        kwargs["extra_property"].append("product")
+
+    wptcommandline.check_args_update(kwargs)
+
+    logger = setup_logging(kwargs, {"mach": sys.stdout})
+
+    updater = WPTUpdate(logger, **kwargs)
+    updater.run()