Add file.filesizes to recipe engine core modules.

README.recipes.md

 <!--- AUTOGENERATED BY `./recipes.py test train` -->
 # Package documentation for [recipe\_engine](https://github.com/luci/recipes-py)
 ## Table of Contents
 
 **[Recipe Modules](#recipe-modules)**
   * [context](#recipe_modules--context) &mdash; The context module provides APIs for manipulating a few pieces of 'ambient' data that affect how steps are run.
   * [file](#recipe_modules--file) &mdash; File manipulation (read/write/delete/glob) methods.
   * [generator_script](#recipe_modules--generator_script) &mdash; A simplistic method for running steps generated by an external script.
   * [json](#recipe_modules--json) &mdash; Methods for producing and consuming JSON.
   * [path](#recipe_modules--path) &mdash; All functions related to manipulating paths in recipes.
@@ skipping 247 matching lines @@
 
 Args:
   * name (str) - The name of the step.
   * dest (Path) - The directory to ensure.
   * mode (int) - The mode to use if the directory doesn't exist. This method
     does not ensure the mode if the directory already exists (if you need
     that behaviour, file a bug).
 
 Raises file.Error if the path exists but is not a directory.
 
+&mdash; **def [filesizes](/recipe_modules/file/api.py#L227)(self, name, files, test_data=None):**
+
+Returns list of filesizes for the given files.
+
+Args:
+  * name (str) - The name of the step.
+  * files (list[Path]) - Paths to files.
+
+Returns list[int], size of each file in bytes.
+
 &mdash; **def [glob\_paths](/recipe_modules/file/api.py#L145)(self, name, source, pattern, test_data=()):**
 
 Performs glob expansion on `pattern`.
 
 glob rules for `pattern` follow the same syntax as for the python `glob`
 stdlib module.
 
 Args:
   * name (str) - The name of the step.
   * source (Path) - The directory whose contents should be globbed.
@@ skipping 53 matching lines @@
 Remove a file.
 
 Does not raise Error if the file doesn't exist.
 
 Args:
   * name (str) - The name of the step.
   * source (Path) - The file to remove.
 
 Raises file.Error.
 
-&mdash; **def [rmcontents](/recipe_modules/file/api.py#L244)(self, name, source):**
+&mdash; **def [rmcontents](/recipe_modules/file/api.py#L266)(self, name, source):**
 
 Similar to rmtree, but removes only contents not the directory.
 
 This is useful e.g. when removing contents of current working directory.
 Deleting current working directory makes all further getcwd calls fail
 until chdir is called. chdir would be tricky in recipes, so we provide
 a call that doesn't delete the directory itself.
 
 Args:
   * name (str) - The name of the step.
   * source (Path) - The directory whose contents should be removed.
 
 Raises file.Error.
 
-&mdash; **def [rmglob](/recipe_modules/file/api.py#L262)(self, name, source, pattern):**
+&mdash; **def [rmglob](/recipe_modules/file/api.py#L284)(self, name, source, pattern):**
 
 Removes all entries in `source` matching the glob `pattern`.
 
 Args:
   * name (str) - The name of the step.
   * source (Path) - The directory whose contents should be filtered and
     removed.
   * pattern (str) - The glob pattern to apply under `source`. Anything
     matching this pattern will be removed.
 
 Raises file.Error.
 
-&mdash; **def [rmtree](/recipe_modules/file/api.py#L227)(self, name, source):**
+&mdash; **def [rmtree](/recipe_modules/file/api.py#L249)(self, name, source):**
 
 Recursively removes a directory.
 
 This uses a native python on Linux/Mac, and uses `rd` on Windows to avoid
 issues w.r.t. path lengths and read-only attributes. If the directory is
 gone already, this returns without error.
 
 Args:
   * name (str) - The name of the step.
   * source (Path) - The directory to remove.
@@ skipping 947 matching lines @@
 
 [DEPS](/recipe_modules/url/tests/join.py#L5): [step](#recipe_modules--step), [url](#recipe_modules--url)
 
 &mdash; **def [RunSteps](/recipe_modules/url/tests/join.py#L11)(api):**
 ### *recipes* / [url:tests/validate\_url](/recipe_modules/url/tests/validate_url.py)
 
 [DEPS](/recipe_modules/url/tests/validate_url.py#L5): [properties](#recipe_modules--properties), [step](#recipe_modules--step), [url](#recipe_modules--url)
 
 &mdash; **def [RunSteps](/recipe_modules/url/tests/validate_url.py#L12)(api):**