Bazel: Add :api rule to build all API artifacts at once

This simplifies house keeping for the CI implementations and this was
always supported in Buck driven build. Wenn new API is added, only one
rule needs to be updated, and all CI implementation would reflect
building of new API without any changes on their side.

Change-Id: I050cef1e1545431d8806bd3a15a267842e3ed809

BUILD

@@ -1,5 +1,6 @@
 package(default_visibility = ["//visibility:public"])
 
+load("//tools/bzl:genrule2.bzl", "genrule2")
 load("//tools/bzl:pkg_war.bzl", "pkg_war")
 
 genrule(
@@ -42,3 +43,30 @@ pkg_war(
     name = "withdocs",
     doc = True,
 )
+
+API_DEPS = [
+  "//gerrit-acceptance-framework:acceptance-framework_deploy.jar",
+  "//gerrit-acceptance-framework:liblib-src.jar",
+  "//gerrit-acceptance-framework:acceptance-framework-javadoc",
+  "//gerrit-extension-api:extension-api_deploy.jar",
+  "//gerrit-extension-api:libapi-src.jar",
+  "//gerrit-extension-api:extension-api-javadoc",
+  "//gerrit-plugin-api:plugin-api_deploy.jar",
+  "//gerrit-plugin-api:plugin-api-sources_deploy.jar",
+  "//gerrit-plugin-api:plugin-api-javadoc",
+  "//gerrit-plugin-gwtui:gwtui-api_deploy.jar",
+  "//gerrit-plugin-gwtui:gwtui-api-source_deploy.jar",
+  "//gerrit-plugin-gwtui:gwtui-api-javadoc",
+]
+
+genrule2(
+    name = 'api',
+    srcs = API_DEPS,
+    testonly = 1,
+    cmd = ' && '.join([
+        'cp $(SRCS) $$TMP',
+        'cd $$TMP',
+        'zip -qr $$ROOT/$@ .',
+    ]),
+    outs = ['api.zip'],
+)

Documentation/dev-bazel.txt

@@ -74,16 +74,14 @@ The output executable WAR will be placed in:
 To build the extension, plugin and GWT API JAR files:
 
 ----
-  bazel build gerrit-plugin-api:plugin-api_deploy.jar
-  bazel build gerrit-extension-api:extension-api_deploy.jar
+  bazel build api
 ----
 
-Java binaries, Java sources and Java docs are generated into corresponding
-project directories, here as example for plugin API:
+The output archive that contains Java binaries, Java sources and
+Java docs will be placed in:
 
 ----
-  bazel-bin/gerrit-plugin-api/plugin-api_deploy.jar
-  bazel-bin/gerrit-extension-api/extension-api_deploy.jar
+  bazel-genfiles/api.zip
 ----
 
 Install {extension,plugin,gwt}-api to the local maven repository: