Add support for Bazel in Gerrit tree build

Change-Id: Ic1a46a529df6af6c0334b5d0142129546df1c8ea

BUILD

diff --git a/BUILD b/BUILD
new file mode 100644
index 0000000..7b9ccaf
--- /dev/null
+++ b/BUILD
@@ -0,0 +1,16 @@
+load("//tools/bzl:plugin.bzl", "gerrit_plugin")
+
+gerrit_plugin(
+    name = "scala-provider",
+    srcs = glob(["src/main/java/**/*.java"]),
+    resources = glob(["src/main/resources/**/*"]),
+    manifest_entries = [
+        "Implementation-Title: Scala Provider",
+        "Implementation-URL: https://gerrit.googlesource.com/plugins/scripting/scala-provider",
+        "Gerrit-PluginName: scala-provider",
+        "Gerrit-Module: com.googlesource.gerrit.plugins.scripting.scala.Module"
+    ],
+    deps = [
+        "@scala_compiler//jar",
+    ],
+)

external_plugin_deps.bzl

diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
new file mode 100644
index 0000000..570bef1
--- /dev/null
+++ b/external_plugin_deps.bzl
@@ -0,0 +1,26 @@
+load("//tools/bzl:maven_jar.bzl", "maven_jar")
+
+def external_plugin_deps():
+  maven_jar(
+    name = 'scala_compiler',
+    artifact = 'org.scala-lang:scala-compiler:2.11.6',
+    sha1 = 'fa7d8a52d53c6571bce334b2c1d3d9546314dde3',
+    exports = [
+      '@scala_reflect//jar',
+    ],
+  )
+
+  maven_jar(
+    name = 'scala_reflect',
+    artifact = 'org.scala-lang:scala-reflect:2.11.6',
+    sha1 = 'f539c9c9cf312472b3a7771ac85ecda859657a1d',
+    exports = [
+      '@scala_library//jar',
+    ],
+  )
+
+  maven_jar(
+    name = 'scala_library',
+    artifact = 'org.scala-lang:scala-library:2.11.6',
+    sha1 = 'be3457b4b748df35bffba675d8cddf44e9df4f7b',
+  )

src/main/resources/Documentation/build.md

diff --git a/src/main/resources/Documentation/build.md b/src/main/resources/Documentation/build.md
index c4fe2d1..5581ebe 100644
--- a/src/main/resources/Documentation/build.md
+++ b/src/main/resources/Documentation/build.md
@@ -1,22 +1,36 @@
 Build
 =====
 
-This plugin is built with Buck.
+This plugin is built with Bazel.
 
-Clone or link this plugin to the plugins directory of Gerrit's source
-tree, and issue the command:
+Clone (or link) this plugin to the `plugins` directory of Gerrit's source tree.
+
+Put the external dependency Bazel build file into the Gerrit /plugins directory,
+replacing the existing empty one.
 
 ```
-  buck build plugins/scala-provider
+  cd gerrit/plugins
+  rm external_plugin_deps.bzl
+  ln -s scala-provider/external_plugin_deps.bzl .
 ```
 
+Then issue
+
+```
+  bazel build plugins/scala-provider
+```
+
+in the root of Gerrit's source tree to build
+
 The output is created in
 
 ```
-  buck-out/gen/plugins/scala-provider/scala-provider.jar
+  bazel-genfiles/plugins/scala-provider/scala-provider.jar
 ```
 
-This project can be imported into the Eclipse IDE:
+This project can be imported into the Eclipse IDE.
+Add the plugin name to the `CUSTOM_PLUGINS` set in
+Gerrit core in `tools/bzl/plugins.bzl`, and execute:
 
 ```
   ./tools/eclipse/project.py