Add backports.weakref to Bazel build

This way people using Bazel don't have to pip install it.

PiperOrigin-RevId: 159057260

tensorflow/python/BUILD

@@ -2464,6 +2464,7 @@ py_library(
     srcs_version = "PY2AND3",
     deps = [
         "//third_party/py/numpy",
+        "@org_python_pypi_backports_weakref",
         "@protobuf//:protobuf_python",
         "@six_archive//:six",
     ],

tensorflow/tools/ci_build/install/install_pip_packages.sh

@@ -85,6 +85,3 @@ pip2 install mock
 
 pip2 install portpicker
 pip3 install portpicker
-
-pip2 install backports.weakref==1.0rc1
-pip3 install backports.weakref==1.0rc1

tensorflow/tools/ci_build/install/install_python3.5_pip_packages.sh

@@ -89,6 +89,3 @@ pip3.5 install wheel==0.29.0
 pip3.5 install portpicker
 
 pip3.5 install werkzeug
-
-pip3.5 install backports.weakref==1.0rc1
-

tensorflow/tools/pip_package/BUILD

@@ -122,6 +122,7 @@ filegroup(
         "@six_archive//:LICENSE",
         "@snappy//:COPYING",
         "@zlib_archive//:zlib.h",
+        "@org_python_pypi_backports_weakref//:LICENSE",
     ] + if_not_windows([
         "@nccl_archive//:LICENSE.txt",
     ]) + tf_additional_license_deps(),

tensorflow/workspace.bzl

@@ -291,13 +291,35 @@ def tf_workspace(path_prefix="", tf_repo_name=""):
       name = "six_archive",
       urls = [
           "http://mirror.bazel.build/pypi.python.org/packages/source/s/six/six-1.10.0.tar.gz",
-          "http://pypi.python.org/packages/source/s/six/six-1.10.0.tar.gz",
+          "https://pypi.python.org/packages/source/s/six/six-1.10.0.tar.gz",
       ],
       sha256 = "105f8d68616f8248e24bf0e9372ef04d3cc10104f1980f54d57b2ce73a5ad56a",
       strip_prefix = "six-1.10.0",
       build_file = str(Label("//third_party:six.BUILD")),
   )
 
+  native.new_http_archive(
+      name = "org_python_pypi_backports_weakref",
+      urls = [
+          "http://mirror.bazel.build/pypi.python.org/packages/bc/cc/3cdb0a02e7e96f6c70bd971bc8a90b8463fda83e264fa9c5c1c98ceabd81/backports.weakref-1.0rc1.tar.gz",
+          "https://pypi.python.org/packages/bc/cc/3cdb0a02e7e96f6c70bd971bc8a90b8463fda83e264fa9c5c1c98ceabd81/backports.weakref-1.0rc1.tar.gz",
+      ],
+      sha256 = "8813bf712a66b3d8b85dc289e1104ed220f1878cf981e2fe756dfaabe9a82892",
+      strip_prefix = "backports.weakref-1.0rc1/src",
+      build_file = str(Label("//third_party:backports_weakref.BUILD")),
+  )
+
+  filegroup_external(
+      name = "org_python_license",
+      licenses = ["notice"],  # Python 2.0
+      sha256_urls = {
+          "b5556e921715ddb9242c076cae3963f483aa47266c5e37ea4c187f77cc79501c": [
+              "http://mirror.bazel.build/docs.python.org/2.7/_sources/license.txt",
+              "https://docs.python.org/2.7/_sources/license.txt",
+          ],
+      },
+  )
+
   native.bind(
       name = "six",
       actual = "@six_archive//:six",
@@ -622,4 +644,3 @@ def tf_workspace(path_prefix="", tf_repo_name=""):
       strip_prefix = "pprof-c0fb62ec88c411cc91194465e54db2632845b650",
       build_file = str(Label("//third_party:pprof.BUILD")),
   )
-

third_party/backports_weakref.BUILD

@@ -0,0 +1,22 @@
+# Description:
+#   Backport of new features in Python's weakref module.
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Python 2.0
+
+py_library(
+    name = "org_python_pypi_backports_weakref",
+    srcs = [
+        "backports/__init__.py",
+        "backports/weakref.py",
+    ],
+    srcs_version = "PY2AND3",
+)
+
+genrule(
+    name = "license",
+    srcs = ["@org_python_license"],
+    outs = ["LICENSE"],
+    cmd = "cp $< $@",
+)