diff --git a/library/linux/Makefile b/library/linux/Makefile
index 6a5810892..03b8ce637 100644
--- a/library/linux/Makefile
+++ b/library/linux/Makefile
@@ -51,7 +51,7 @@ $(LIBRARY_OUT): $(SOURCES) $(HEADERS) $(LIBRARIES)
 # avoiding unnecessary relinks.
 $(FLUTTER_ENGINE_LIB_FILE) $(FLUTTER_ENGINE_HEADER_DIR)/$(FLUTTER_ENGINE_HEADER): \
 		$(FLUTTER_DIR)/bin/internal/engine.version
-	$(ENGINE_UPDATER) --flutter_root=$(FLUTTER_DIR) ./
+	$(ENGINE_UPDATER) ./
 	if [ -f $(FLUTTER_ENGINE_HEADER) ]; then \
 		mkdir -p $(FLUTTER_ENGINE_HEADER_DIR) && \
 		mv $(FLUTTER_ENGINE_HEADER) $(FLUTTER_ENGINE_HEADER_DIR)/; \
diff --git a/library/macos/FlutterEmbedderMac.xcodeproj/project.pbxproj b/library/macos/FlutterEmbedderMac.xcodeproj/project.pbxproj
index 0b730ac53..77c7171bd 100644
--- a/library/macos/FlutterEmbedderMac.xcodeproj/project.pbxproj
+++ b/library/macos/FlutterEmbedderMac.xcodeproj/project.pbxproj
@@ -302,7 +302,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/bash;
-			shellScript = "readonly TOOLS_DIR=\"$PROJECT_DIR\"/../../tools\n\"$TOOLS_DIR\"/update_flutter_engine --flutter_root=\"$(\"$TOOLS_DIR\"/flutter_location)\" \"$PROJECT_DIR\"/../../../flutter_engine_framework/macos";
+			shellScript = "readonly TOOLS_DIR=\"$PROJECT_DIR\"/../../tools\n\"$TOOLS_DIR\"/update_flutter_engine \"$PROJECT_DIR\"/../../../flutter_engine_framework/macos";
 		};
 /* End PBXShellScriptBuildPhase section */
 
diff --git a/tools/run_dart_tool b/tools/run_dart_tool
new file mode 100755
index 000000000..0d645b1a6
--- /dev/null
+++ b/tools/run_dart_tool
@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+#
+# Copyright 2019 Google LLC
+#
+# 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.
+
+# Takes the name of a tool in dart_tools/bin (without the .dart extension),
+# as well as any parameters to that tool, then runs it with those parameters
+# using the version of Dart from the Flutter tree.
+
+readonly base_dir="$(dirname "$0")"
+readonly flutter_dir="$("${base_dir}/flutter_location")"
+readonly flutter_bin_dir="${flutter_dir}/bin"
+readonly dart_bin_dir="${flutter_bin_dir}/cache/dart-sdk/bin"
+
+# Ensure that the Dart SDK has been downloaded.
+if [[ ! -e ${dart_bin_dir} ]]; then
+  "${flutter_bin_dir}/flutter" precache
+fi
+
+readonly tool_script="${base_dir}/dart_tools/bin/$1.dart"
+exec "${dart_bin_dir}/dart" "${tool_script}" "${@:2}"
diff --git a/tools/run_dart_tool.bat b/tools/run_dart_tool.bat
new file mode 100644
index 000000000..1cc4b4d39
--- /dev/null
+++ b/tools/run_dart_tool.bat
@@ -0,0 +1,26 @@
+:: Copyright 2019 Google LLC
+::
+:: 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.
+@echo off
+
+for /f "delims=" %%i in ('%~dp0flutter_location') do set FLUTTER_DIR=%%i
+set FLUTTER_BIN_DIR=%FLUTTER_DIR%\bin
+set DART_BIN_DIR=%FLUTTER_BIN_DIR%\cache\dart-sdk\bin
+
+:: Ensure that the Dart SDK has been downloaded.
+if not exist %DART_BIN_DIR%\ call %FLUTTER_BIN_DIR%\flutter precache
+
+set DART_TOOL=%1
+for /f "tokens=1,*" %%a in ("%*") do set TOOL_PARAMS=%%b
+
+call %DART_BIN_DIR%\dart %~dp0.\dart_tools\bin\%DART_TOOL%.dart %TOOL_PARAMS%
diff --git a/tools/update_flutter_engine b/tools/update_flutter_engine
index e6e655549..913935b3f 100755
--- a/tools/update_flutter_engine
+++ b/tools/update_flutter_engine
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# 
+#
 # Copyright 2018 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -13,12 +13,11 @@
 # 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.
+
+# Runs update_flutter_engine.dart, using the output of flutter_location as
+# --flutter_root
+
 readonly base_dir="$(dirname "$0")"
-readonly flutter_dir="$("$base_dir/flutter_location")"
-readonly flutter_bin_dir="$flutter_dir/bin"
-readonly dart_bin_dir="$flutter_bin_dir/cache/dart-sdk/bin"
-# Ensure that the Dart SDK has been downloaded.
-if [[ ! -e $dart_bin_dir ]]; then
-  "$flutter_bin_dir/flutter" precache
-fi
-exec "$dart_bin_dir/dart" "$base_dir/dart_tools/bin/update_flutter_engine.dart" "$@"
+readonly flutter_dir="$("${base_dir}/flutter_location")"
+exec "${base_dir}/run_dart_tool" update_flutter_engine \
+	--flutter_root="${flutter_dir}" "$@"
diff --git a/tools/update_flutter_engine.bat b/tools/update_flutter_engine.bat
index 612eb68ee..4ae0dc0ad 100644
--- a/tools/update_flutter_engine.bat
+++ b/tools/update_flutter_engine.bat
@@ -11,13 +11,11 @@
 :: 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.
+
+:: Runs update_flutter_engine.dart, using the output of flutter_location.bat as
+:: --flutter_root
 @echo off
 
 for /f "delims=" %%i in ('%~dp0flutter_location') do set FLUTTER_DIR=%%i
-set FLUTTER_BIN_DIR=%FLUTTER_DIR%\bin
-set DART_BIN_DIR=%FLUTTER_BIN_DIR%\cache\dart-sdk\bin
-
-:: Ensure that the Dart SDK has been downloaded.
-if not exist %DART_BIN_DIR%\ call %FLUTTER_BIN_DIR%\flutter precache
 
-call %DART_BIN_DIR%\dart %~dp0.\dart_tools\bin\update_flutter_engine.dart --flutter_root %FLUTTER_DIR% %*
+call %~dp0.\run_dart_tool update_flutter_engine --flutter_root %FLUTTER_DIR% %*