Add default values for optional parameters. (#27197)

diff --git a/packages/flutter_tools/lib/src/build_runner/build_kernel_compiler.dart b/packages/flutter_tools/lib/src/build_runner/build_kernel_compiler.dart
index af9b8f7..d60bc8c 100644
--- a/packages/flutter_tools/lib/src/build_runner/build_kernel_compiler.dart
+++ b/packages/flutter_tools/lib/src/build_runner/build_kernel_compiler.dart

@@ -33,7 +33,7 @@
     List<String> fileSystemRoots,
     String fileSystemScheme,
     String depFilePath,
-    TargetModel targetModel,
+    TargetModel targetModel = TargetModel.flutter,
   }) async {
     if (fileSystemRoots != null || fileSystemScheme != null || depFilePath != null || targetModel != null || sdkRoot != null || packagesPath != null) {
       printTrace('fileSystemRoots, fileSystemScheme, depFilePath, targetModel,'

diff --git a/packages/flutter_tools/lib/src/commands/daemon.dart b/packages/flutter_tools/lib/src/commands/daemon.dart
index de597b3..b73f41f 100644
--- a/packages/flutter_tools/lib/src/commands/daemon.dart
+++ b/packages/flutter_tools/lib/src/commands/daemon.dart

@@ -784,7 +784,7 @@
     String message, {
     @required Duration timeout,
     String progressId,
-    bool multilineOutput,
+    bool multilineOutput = false,
     int progressIndicatorPadding = kDefaultStatusPadding,
   }) {
     assert(timeout != null);
@@ -961,8 +961,8 @@
     String message, {
     @required Duration timeout,
     String progressId,
-    bool multilineOutput,
-    int progressIndicatorPadding = 52,
+    bool multilineOutput = false,
+    int progressIndicatorPadding = kDefaultStatusPadding,
   }) {
     assert(timeout != null);
     final int id = _nextProgressId++;

diff --git a/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart b/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart
index 84bc1ba..7ed0462 100644
--- a/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart
+++ b/packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart

@@ -185,7 +185,7 @@
     Map<String, dynamic> platformArgs,
     bool prebuiltApplication = false,
     bool applicationNeedsRebuild = false,
-    bool usesTerminalUi = false,
+    bool usesTerminalUi = true,
     bool ipv6 = false,
   }) => Future<void>.error('unimplemented');
 

diff --git a/packages/flutter_tools/test/base/build_test.dart b/packages/flutter_tools/test/base/build_test.dart
index f2f79fc..ca110fa 100644
--- a/packages/flutter_tools/test/base/build_test.dart
+++ b/packages/flutter_tools/test/base/build_test.dart

@@ -55,7 +55,7 @@
     String packagesPath,
     String depfilePath,
     IOSArch iosArch,
-    Iterable<String> additionalArgs,
+    Iterable<String> additionalArgs = const <String>[],
   }) async {
     _callCount += 1;
     _snapshotType = snapshotType;

diff --git a/packages/flutter_tools/test/crash_reporting_test.dart b/packages/flutter_tools/test/crash_reporting_test.dart
index 7152ba5..f3255c6 100644
--- a/packages/flutter_tools/test/crash_reporting_test.dart
+++ b/packages/flutter_tools/test/crash_reporting_test.dart

@@ -216,10 +216,10 @@
   void write(_) {}
 
   @override
-  void writeAll(_, [__]) {}
+  void writeAll(_, [__ = '']) {}
 
   @override
-  void writeln([_]) {}
+  void writeln([_ = '']) {}
 
   @override
   void writeCharCode(_) {}

diff --git a/packages/flutter_tools/test/emulator_test.dart b/packages/flutter_tools/test/emulator_test.dart
index 59b276d..7a7c5b4 100644
--- a/packages/flutter_tools/test/emulator_test.dart
+++ b/packages/flutter_tools/test/emulator_test.dart

@@ -203,8 +203,8 @@
     Map<String, String> environment,
     bool includeParentEnvironment = true,
     bool runInShell = false,
-    Encoding stdoutEncoding,
-    Encoding stderrEncoding
+    Encoding stdoutEncoding = systemEncoding,
+    Encoding stderrEncoding = systemEncoding
   }) {
     final String program = command[0];
     final List<String> args = command.sublist(1);