Implement ListenableFuturePagedSource

Provides a Java-friendly API leveraging Guava's ListenableFuture
wrapping the suspending PagedSource API

Test: ./gradlew paging:paging-guava:cC
Change-Id: I0add2127d23223bbcc8f1f19ce5b0b52003a1153

paging/guava/build.gradle

diff --git a/paging/guava/build.gradle b/paging/guava/build.gradle
new file mode 100644
index 0000000..d5360f9
--- /dev/null
+++ b/paging/guava/build.gradle
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import static androidx.build.dependencies.DependenciesKt.*
+import androidx.build.LibraryGroups
+import androidx.build.LibraryVersions
+import androidx.build.AndroidXExtension
+import androidx.build.Publish
+
+plugins {
+    id("AndroidXPlugin")
+    id("com.android.library")
+    id("kotlin-android")
+}
+
+dependencies {
+    api(project(":paging:paging-common"))
+    api(KOTLIN_STDLIB)
+    api(project(":concurrent:concurrent-futures-ktx"))
+
+    testImplementation project(':internal-testutils-common')
+    testImplementation(JUNIT)
+    testImplementation(KOTLIN_TEST)
+}
+
+androidx {
+    name = "Android Paging Guava"
+    publish = Publish.SNAPSHOT_AND_RELEASE
+    mavenVersion = LibraryVersions.PAGING
+    mavenGroup = LibraryGroups.PAGING
+    inceptionYear = "2019"
+    description = "Android Paging Guava"
+    url = AndroidXExtension.ARCHITECTURE_URL
+}