title: Getting error while upgrade the flutter version 2.0
body: <p>I getting an error while trying to run the flutter app in a web browser.</p>
  <p>Following is the output that I am getting while running the app :</p>
  <pre><code>Launching lib/main.dart on Chrome in debug mode...
  
  Waiting for connection from debug service on Chrome...
  ../../../.pub-cache/hosted/pub.dartlang.org/wav
  
  e-0.1.0/lib/config.dart:46:13: Error: Method not found: 'throwNullError'.
                  throwNullError('custom', 'colors` or `gradients');
                  ^^^^^^^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/wave-0.1.0/lib/config.dart:60:13: Error: Method not found: 'throwNullError'.
                  throwNullError('custom', 'durations');
                  ^^^^^^^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/wave-0.1.0/lib/config.dart:66:13: Error: Method not found: 'throwNullError'.
                  throwNullError('custom', 'heightPercentages');
                  ^^^^^^^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/flutter_platform_widgets-0.60.2/lib/src/platform_app_bar.dart:209:9: Error: No named parameter with the name 'actionsForegroundColor'.
              actionsForegroundColor: data?.actionsForegroundColor,
              ^^^^^^^^^^^^^^^^^^^^^^
      ../../FlutterProjects/SDK/flutter/packages/flutter/lib/src/cupertino/nav_bar.dart:220:9: Context: Found this candidate, but the arguments don't match.
        const CupertinoNavigationBar({
              ^^^^^^^^^^^^^^^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/flutter_platform_widgets-0.60.2/lib/src/platform_app_bar.dart:229:7: Error: No named parameter with the name 'actionsForegroundColor'.
            actionsForegroundColor: data?.actionsForegroundColor,
            ^^^^^^^^^^^^^^^^^^^^^^
      ../../FlutterProjects/SDK/flutter/packages/flutter/lib/src/cupertino/nav_bar.dart:220:9: Context: Found this candidate, but the arguments don't match.
        const CupertinoNavigationBar({
              ^^^^^^^^^^^^^^^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/flutter_neumorphic-3.0.3/lib/src/widget/app_bar.dart:147:57: Error: No named parameter with the name 'nullOk'.
          final ScaffoldState scaffold = Scaffold.of(context, nullOk: true);
                                                              ^^^^^^
      ../../FlutterProjects/SDK/flutter/packages/flutter/lib/src/material/scaffold.dart:1930:24: Context: Found this candidate, but the arguments don't match.
        static ScaffoldState of(BuildContext context) {
                             ^^
      ../../FlutterProjects/SDK/flutter/packages/flutter_localizations/lib/src/material_localizations.dart:413:7: Error: Method 'replaceFirst' cannot be called on 'String?' because it is potentially null.
      Try calling using ?. instead.
          ).replaceFirst(r'$selectedRowCount', formatDecimal(selectedRowCount));
            ^^^^^^^^^^^^
      ../../FlutterProjects/SDK/flutter/packages/flutter_localizations/lib/src/material_localizations.dart:550:7: Error: Method 'replaceFirst' cannot be called on 'String?' because it is potentially null.
      Try calling using ?. instead.
          ).replaceFirst(r'$licenseCount', formatDecimal(licenseCount));
            ^^^^^^^^^^^^
      ../../FlutterProjects/SDK/flutter/packages/flutter_localizations/lib/src/material_localizations.dart:659:7: Error: Method 'replaceFirst' cannot be called on 'String?' because it is potentially null.
      Try calling using ?. instead.
          ).replaceFirst(r'$remainingCount', formatDecimal(remainingCount));
            ^^^^^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/chewie-0.9.10/lib/src/chewie_player.dart:83:7: Error: No named parameter with the name 'resizeToAvoidBottomPadding'.
            resizeToAvoidBottomPadding: false,
            ^^^^^^^^^^^^^^^^^^^^^^^^^^
      ../../FlutterProjects/SDK/flutter/packages/flutter/lib/src/material/scaffold.dart:1437:9: Context: Found this candidate, but the arguments don't match.
        const Scaffold({
              ^^^^^^^^
      ../../../.pub-cache/hosted/pub.dartlang.org/chewie-0.9.10/lib/src/chewie_player.dart:276:17: Error: The method 'inheritFromWidgetOfExactType' isn't defined for the class 'BuildContext'.
       - 'BuildContext' is from 'package:flutter/src/widgets/framework.dart' ('../../FlutterProjects/SDK/flutter/packages/flutter/lib/src/widgets/framework.dart').
      Try correcting the name to the name of an existing method, or defining a method named 'inheritFromWidgetOfExactType'.
              context.inheritFromWidgetOfExactType(_ChewieControllerProvider)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      Failed to compile application.
  </code></pre>
  <p>Following is my flutter doctor output:</p>
  <pre><code>[✓] Flutter (Channel master, 1.26.0-2.0.pre.419, on macOS 11.1 20C69 darwin-x64, locale en-GB)
      • Flutter version 1.26.0-2.0.pre.419 at /Users/sanket/Desktop/FlutterProjects/SDK/flutter
      • Framework revision 913d5933c1 (4 hours ago), 2021-01-19 22:34:03 -0800
      • Engine revision b58dbc88fc
      • Dart version 2.12.0 (build 2.12.0-240.0.dev)
  
  [✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
      • Android SDK at /Users/sanket/Library/Android/sdk
      • Platform android-30, build-tools 30.0.2
      • ANDROID_HOME = /Users/sanket/Library/Android/sdk
      • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
      • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
      • All Android licenses accepted.
  
  [!] Xcode - develop for iOS and macOS
      • Xcode at /Applications/Xcode2.app/Contents/Developer
      • Xcode 12.0, Build version 12A7209
      ! Xcode 12.0.0 out of date (12.0.1 is recommended).
        Download the latest version or update via the Mac App Store.
      • CocoaPods version 1.10.0
  
  [✓] Chrome - develop for the web
      • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
  
  [✓] Android Studio (version 4.1)
      • Android Studio at /Applications/Android Studio.app/Contents
      • Flutter plugin can be installed from:
         https://plugins.jetbrains.com/plugin/9212-flutter
      • Dart plugin can be installed from:
         https://plugins.jetbrains.com/plugin/6351-dart
      • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
  
  [✓] Connected device (2 available)
      • AOSP on IA Emulator (mobile) • emulator-5554 • android-x86    • Android 9 (API 28) (emulator)
      • Chrome (web)                 • chrome        • web-javascript • Google Chrome 87.0.4280.141
  
  ! Doctor found issues in 1 category.
  Process finished with exit code 0
  </code></pre>
  <p><a href="https://i.stack.imgur.com/Ogxtg.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Ogxtg.png" alt="enter image description here" /></a></p>
  <p>Please help me out to solve this error, My app earlier running in the browser but I don't know when it stopped working.</p>
  <p>I tried to upgrade the flutter and dart version to solve this issue but still not working.</p>