Closes MozillaReality#1397: Megazord support

(currently built against local versions of a-c, since upstream work is still inflight)

This PR upgrades a-c to 5.0.0, which is now using 0.35.0 appservices release
that introduces a "default megazord", which is what the consuming application
now uses by default.

See megazord docs: https://mozilla.github.io/application-services/docs/applications/consuming-megazord-libraries.html

TODO
- we want to use Gecko's network stack

app/build.gradle

@@ -405,6 +405,8 @@ dependencies {
     implementation deps.android_components.ui_autocomplete
     implementation deps.android_components.concept_fetch
     implementation deps.android_components.lib_fetch
+    implementation deps.android_components.rusthttp
+    implementation deps.android_components.rustlog
 
     // TODO this should not be necessary at all, see Services.kt
     implementation deps.work.runtime

app/src/common/shared/org/mozilla/vrbrowser/VRBrowserApplication.kt

@@ -0,0 +1,51 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * 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/. */
+
+package org.mozilla.vrbrowser
+
+import android.app.Application
+
+import org.mozilla.vrbrowser.browser.Places
+import org.mozilla.vrbrowser.browser.Services
+import org.mozilla.vrbrowser.db.AppDatabase
+import org.mozilla.vrbrowser.telemetry.TelemetryWrapper
+
+import mozilla.components.lib.fetch.httpurlconnection.HttpURLConnectionClient
+import mozilla.components.support.base.log.Log
+import mozilla.components.support.base.log.sink.AndroidLogSink
+import mozilla.components.support.rusthttp.RustHttpConfig
+import mozilla.components.support.rustlog.RustLog
+
+class VRBrowserApplication : Application() {
+
+    private var appExecutors: AppExecutors? = null
+    lateinit var services: Services
+        private set
+    lateinit var places: Places
+        private set
+
+    private val database: AppDatabase
+        get() = AppDatabase.getInstance(this, appExecutors)
+
+    val repository: DataRepository
+        get() = DataRepository.getInstance(database, appExecutors)
+
+    override fun onCreate() {
+        super.onCreate()
+
+        // Enable android-components and application-services logging.
+        Log.addSink(AndroidLogSink())
+        RustLog.enable()
+
+        // Specify network stack to be used by application-services libraries.
+        RustHttpConfig.setClient(lazy { HttpURLConnectionClient() })
+
+        appExecutors = AppExecutors()
+        places = Places(this)
+        services = Services(this, places)
+
+        TelemetryWrapper.init(this)
+    }
+}

versions.gradle

@@ -25,7 +25,7 @@ def versions = [:]
 // GeckoView versions can be found here:
 // https://maven.mozilla.org/?prefix=maven2/org/mozilla/geckoview/
 versions.gecko_view = "70.0.20190710094220"
-versions.android_components = "4.0.0"
+versions.android_components = "5.0.0-SNAPSHOT"
 versions.mozilla_speech = "1.0.6"
 versions.openwnn = "1.3.7"
 versions.google_vr = "1.190.0"
@@ -59,6 +59,8 @@ android_components.service_accounts = "org.mozilla.components:service-firefox-ac
 android_components.ui_autocomplete = "org.mozilla.components:ui-autocomplete:$versions.android_components"
 android_components.concept_fetch = "org.mozilla.components:concept-fetch:$versions.android_components"
 android_components.lib_fetch = "org.mozilla.components:lib-fetch-httpurlconnection:$versions.android_components"
+android_components.rustlog = "org.mozilla.components:support-rustlog:$versions.android_components"
+android_components.rusthttp = "org.mozilla.components:support-rusthttp:$versions.android_components"
 deps.android_components = android_components
 
 deps.mozilla_speech = "com.github.mozilla:mozillaspeechlibrary:$versions.mozilla_speech"
@@ -145,6 +147,7 @@ def addRepos(RepositoryHandler handler) {
     handler.google()
     handler.jcenter()
     handler.maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }
+    handler.maven { url 'https://snapshots.maven.mozilla.org/maven2' }
     handler.maven { url 'https://maven.mozilla.org/maven2' }
     handler.maven { url 'https://download.servo.org/nightly/maven' }
 }