diff --git a/packages/flutter_tools/lib/src/commands/build_apk.dart b/packages/flutter_tools/lib/src/commands/build_apk.dart
index 132f2b2ce7d..eadf964dcb0 100644
--- a/packages/flutter_tools/lib/src/commands/build_apk.dart
+++ b/packages/flutter_tools/lib/src/commands/build_apk.dart
@@ -201,46 +201,11 @@ class BuildApkCommand extends FlutterCommand {
 
   @override
   Future<int> runInProject() async {
-    // Validate that we can find an android sdk.
-    if (androidSdk == null) {
-      printError('No Android SDK found. Try setting the ANDROID_HOME environment variable.');
-      return 1;
-    }
-
-    List<String> validationResult = androidSdk.validateSdkWellFormed();
-    if (validationResult.isNotEmpty) {
-      validationResult.forEach(printError);
-      printError('Try re-installing or updating your Android SDK.');
-      return 1;
-    }
-
-    BuildMode mode = getBuildMode();
-
-    Map<String, File> extraFiles = <String, File>{};
-    for (String addFile in argResults['add-file']) {
-      List<String> keyValue = addFile.split('=');
-      if (keyValue.length != 2) {
-        printError('add-file option must have the format <path/in/APK>=<local/file/path>');
-        return 1;
-      }
-      extraFiles[keyValue.first] = new File(keyValue.last);
-    }
-
-    if (FileSystemEntity.isDirectorySync(_kDefaultAssetsPath)) {
-      Directory assetsDir = new Directory(_kDefaultAssetsPath);
-      for (FileSystemEntity entity in assetsDir.listSync(recursive: true)) {
-        if (entity is File) {
-          String targetPath = entity.path.substring(assetsDir.path.length);
-          extraFiles["assets/$targetPath"] = entity;
-        }
-      };
-    }
-
     // TODO(devoncarew): This command should take an arg for the output type (arm / x64).
 
     return await buildAndroid(
       TargetPlatform.android_arm,
-      mode,
+      getBuildMode(),
       force: true,
       manifest: argResults['manifest'],
       resources: argResults['resources'],
@@ -248,7 +213,7 @@ class BuildApkCommand extends FlutterCommand {
       target: argResults['target'],
       flxPath: argResults['flx'],
       aotPath: argResults['aot-path'],
-      extraFiles: extraFiles,
+      addFiles: argResults['add-file'],
       keystore: (argResults['keystore'] ?? '').isEmpty ? null : new ApkKeystoreInfo(
         keystore: argResults['keystore'],
         password: argResults['keystore-password'],
@@ -427,16 +392,19 @@ int _signApk(
 }
 
 // Returns true if the apk is out of date and needs to be rebuilt.
-bool _needsRebuild(String apkPath, String manifest) {
+bool _needsRebuild(String apkPath, String manifest, Map<String, File> extraFiles) {
   FileStat apkStat = FileStat.statSync(apkPath);
   // Note: This list of dependencies is imperfect, but will do for now. We
   // purposely don't include the .dart files, because we can load those
   // over the network without needing to rebuild (at least on Android).
-  Iterable<FileStat> dependenciesStat = <String>[
+  List<String> dependencies = <String>[
     manifest,
     _kFlutterManifestPath,
     _kPackagesStatusPath
-  ].map((String path) => FileStat.statSync(path));
+  ];
+  dependencies.addAll(extraFiles.values.map((File file) => file.path));
+  Iterable<FileStat> dependenciesStat =
+    dependencies.map((String path) => FileStat.statSync(path));
 
   if (apkStat.type == FileSystemEntityType.NOT_FOUND)
     return true;
@@ -462,7 +430,7 @@ Future<int> buildAndroid(
   String target,
   String flxPath,
   String aotPath,
-  Map<String, File> extraFiles,
+  List<String> addFiles,
   ApkKeystoreInfo keystore
 }) async {
   // Validate that we can find an android sdk.
@@ -478,7 +446,27 @@ Future<int> buildAndroid(
     return 1;
   }
 
-  if (!force && !_needsRebuild(outputFile, manifest)) {
+  Map<String, File> extraFiles = <String, File>{};
+  for (String addFile in addFiles ?? <String>[]) {
+    List<String> keyValue = addFile.split('=');
+    if (keyValue.length != 2) {
+      printError('add-file option must have the format <path/in/APK>=<local/file/path>');
+      return 1;
+    }
+    extraFiles[keyValue.first] = new File(keyValue.last);
+  }
+
+  if (FileSystemEntity.isDirectorySync(_kDefaultAssetsPath)) {
+    Directory assetsDir = new Directory(_kDefaultAssetsPath);
+    for (FileSystemEntity entity in assetsDir.listSync(recursive: true)) {
+      if (entity is File) {
+        String targetPath = entity.path.substring(assetsDir.path.length);
+        extraFiles["assets/$targetPath"] = entity;
+      }
+    };
+  }
+
+  if (!force && !_needsRebuild(outputFile, manifest, extraFiles)) {
     printTrace('APK up to date; skipping build step.');
     return 0;
   }