Bazel: Make build tool chain python 3 compatible

This change establishes Python 3 compatibility for the major part of
Gerrit build tool chain. Only two scripts remain non Python 3
compatible:

* Documentation/replace_macros.py
* tools/bzl/license-map.py

Those scripts explicitly invoked with python2 version.

Test Plan:

a. Python 2.7

* Switch to system where /usr/bin/python points to Python 2.7
* bazel build release
* bazel test //...
* tools/eclipse/project.py

b. Python 3.6

* Switch to system where /usr/bin/python points to Python 3.6
* bazel build release
* bazel test //...
* tools/eclipse/project.py

Pre-requisites for the test plan:

In case bazel action and repository caching is activated on the SUT, the
caches would need to be wiped out, to make sure that the complete build
tool chain was tested. On my system I had to run these commands:

* bazel clean --expunge_async
* rm -rf ~/.gerritcodereview/buck-cache/downloaded-artifacts/*
* rm -rf ~/.gerritcodereview/bazel-cache/cas/*
* rm -rf ~/.gerritcodereview/bazel-cache/repository/*

Bug: Issue 8151
Change-Id: Iece59d0c5149b77a02754b3fed4ce84d5d8085ee
(cherry picked from commit 0c9e13c11a)

Documentation/replace_macros.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 # coding=utf-8
 # Copyright (C) 2013 The Android Open Source Project
 #

tools/bzl/license.bzl

@@ -25,7 +25,7 @@ def license_map(name, targets = [], opts = [], **kwargs):
   # post process the XML into our favorite format.
   native.genrule(
     name = "gen_license_txt_" + name,
-    cmd = "python $(location //tools/bzl:license-map.py) %s %s > $@" % (" ".join(opts), " ".join(xmls)),
+    cmd = "python2 $(location //tools/bzl:license-map.py) %s %s > $@" % (" ".join(opts), " ".join(xmls)),
     outs = [ name + ".txt" ],
     tools = tools,
     **kwargs

tools/eclipse/project.py

@@ -262,7 +262,7 @@ def gen_factorypath(ext):
     doc.writexml(fd, addindent='\t', newl='\n', encoding='UTF-8')
 
 try:
-  ext_location = retrieve_ext_location()
+  ext_location = retrieve_ext_location().decode("utf-8")
   gen_project(args.project_name)
   gen_classpath(ext_location)
   gen_factorypath(ext_location)

tools/js/bowerutil.py

@@ -40,7 +40,7 @@ def hash_bower_component(hash_obj, path):
       if f == '.bower.json':
         continue
       p = os.path.join(root, f)
-      hash_obj.update(p[len(path)+1:])
-      hash_obj.update(open(p).read())
+      hash_obj.update(p[len(path)+1:].encode("utf-8"))
+      hash_obj.update(open(p, "rb").read())
 
   return hash_obj

tools/js/download_bower.py

@@ -68,7 +68,7 @@ def ignore_deps(info):
   deps = info.get('dependencies')
   if deps:
     with open(os.path.join('.bowerrc'), 'w') as f:
-      json.dump({'ignoredDependencies': deps.keys()}, f)
+      json.dump({'ignoredDependencies': list(deps.keys())}, f)
 
 
 def cache_entry(name, package, version, sha1):

tools/js/npm_pack.py

@@ -36,7 +36,7 @@ def is_bundled(tar):
 def bundle_dependencies():
   with open('package.json') as f:
     package = json.load(f)
-  package['bundledDependencies'] = package['dependencies'].keys()
+  package['bundledDependencies'] = list(package['dependencies'].keys())
   with open('package.json', 'w') as f:
     json.dump(package, f)