[automation] Re-add project-specific Mentat Docker image.

automation/docker/Dockerfile

@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+FROM mozillamobile/rust-component:buildtools-27.0.3-ndk-r17b-ndk-version-26-rust-stable-rust-beta
+
+MAINTAINER Nick Alexander "nalexander@mozilla.com"
+
+#----------------------------------------------------------------------------------------------------------------------
+#-- Project -----------------------------------------------------------------------------------------------------------
+#----------------------------------------------------------------------------------------------------------------------
+
+ENV PROJECT_REPOSITORY "https://github.com/mozilla/mentat.git"
+
+RUN git clone $PROJECT_REPOSITORY
+
+WORKDIR /build/mentat
+
+# Temporary.
+RUN git fetch origin master && git checkout origin/generic-automation-images && git show-ref HEAD
+
+# Populate dependencies.
+RUN ./sdks/android/Mentat/gradlew --no-daemon -p sdks/android/Mentat tasks
+
+# Build Rust.
+RUN ./sdks/android/Mentat/gradlew --no-daemon -p sdks/android/Mentat cargoBuild
+
+# Actually build.  In the future, we might also lint (to cache additional dependencies).
+RUN ./sdks/android/Mentat/gradlew --no-daemon -p sdks/android/Mentat assemble test
+
+#----------------------------------------------------------------------------------------------------------------------
+# -- Cleanup ----------------------------------------------------------------------------------------------------------
+#----------------------------------------------------------------------------------------------------------------------
+
+# Drop built Rust artifacts.
+RUN cargo clean

sdks/android/Mentat/build.gradle

@@ -29,13 +29,14 @@ buildscript {
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.7.3'
         classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'
 
-        classpath 'gradle.plugin.org.mozilla.rust-android-gradle:plugin:0.1.0'
+        classpath 'gradle.plugin.org.mozilla.rust-android-gradle:plugin:0.2.0'
-        // NOTE: Do not place your application dependencies here; they belong
-        // in the individual module build.gradle files
 
         // Yes, this is unusual.  We want to access some host-specific
         // computation at build time.
         classpath 'net.java.dev.jna:jna:4.5.2'
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
     }
 }