Fix isMouseEvent returning false for simulated context menu events

Dockerfile

@@ -1,21 +1,12 @@
 FROM drydock-prod.workiva.net/workiva/dart_build_image:1
 
-# Chrome install taken from https://github.com/Workiva/dart_unit_test_image/blob/master@%7B13-01-2021%7D/Dockerfile
-
-# Set the expected Chrome major version. This allows us to update the expected version when
-# we need to roll out a new version of this base image with a new chrome version as the only change
-ENV EXPECTED_CHROME_VERSION=87
-
-# Install Chrome
+# Chrome install adapted from https://github.com/Workiva/dart_unit_test_image/blob/master@%7B13-01-2021%7D/Dockerfile
 RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add - && \
     echo 'deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main' | tee /etc/apt/sources.list.d/google-chrome.list && \
     apt-get -qq update && apt-get install -y google-chrome-stable && \
     mv /usr/bin/google-chrome-stable /usr/bin/google-chrome && \
     sed -i --follow-symlinks -e 's/\"\$HERE\/chrome\"/\"\$HERE\/chrome\" --no-sandbox/g' /usr/bin/google-chrome
 
-# Fail the build if the version doesn't match what we expected
-RUN google-chrome --version | grep " $EXPECTED_CHROME_VERSION\."
-
 # TODO: Remove this and instead run it within the github actions CI on the stable channel once SDK lower bound is >=2.9.3
 RUN dartfmt --line-length=120 --dry-run --set-exit-if-changed .
 
@@ -46,22 +37,13 @@ RUN apt-get install -y \
 	wget \
 	&& rm -rf /var/lib/apt/lists/*
 
-# Chrome install taken from https://github.com/Workiva/dart_unit_test_image/blob/master@%7B13-01-2021%7D/Dockerfile
-
-# Set the expected Chrome major version. This allows us to update the expected version when
-# we need to roll out a new version of this base image with a new chrome version as the only change
-ENV EXPECTED_CHROME_VERSION=87
-
-# Install Chrome
+# Chrome install adapted from https://github.com/Workiva/dart_unit_test_image/blob/master@%7B13-01-2021%7D/Dockerfile
 RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add - && \
     echo 'deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main' | tee /etc/apt/sources.list.d/google-chrome.list && \
     apt-get -qq update && apt-get install -y google-chrome-stable && \
     mv /usr/bin/google-chrome-stable /usr/bin/google-chrome && \
     sed -i --follow-symlinks -e 's/\"\$HERE\/chrome\"/\"\$HERE\/chrome\" --no-sandbox/g' /usr/bin/google-chrome
 
-# Fail the build if the version doesn't match what we expected
-RUN google-chrome --version | grep " $EXPECTED_CHROME_VERSION\."
-
 WORKDIR /build/
 ADD . /build/
 

lib/src/react_client/event_helpers.dart

@@ -783,7 +783,8 @@ extension SyntheticEventTypeHelpers on SyntheticEvent {
       (_hasProperty('relatedTarget') && !_hasProperty('button')) || _checkEventType(const ['focus', 'blur']);
 
   /// Uses Duck Typing to detect if the event instance is a [SyntheticMouseEvent].
-  bool get isMouseEvent => _hasProperty('button') || _checkEventType(const ['mouse', 'click', 'drag', 'drop']);
+  bool get isMouseEvent =>
+      _hasProperty('button') || _checkEventType(const ['mouse', 'click', 'drag', 'drop', 'contextmenu']);
 
   /// Uses Duck Typing to detect if the event instance is a [SyntheticPointerEvent].
   bool get isPointerEvent => _hasProperty('pointerId') || _checkEventType(const ['pointer']);

test/react_test_utils_test.dart

@@ -158,6 +158,7 @@ testUtils({isComponent2: false, dynamic eventComponent, dynamic sampleComponent,
       group('compositionStart', () => testEvent(Simulate.compositionStart, 'compositionStart', expectCompositionEvent));
       group('compositionUpdate',
           () => testEvent(Simulate.compositionUpdate, 'compositionUpdate', expectCompositionEvent));
+      group('contextMenu', () => testEvent(Simulate.contextMenu, 'contextMenu', expectMouseEvent));
       group('cut', () => testEvent(Simulate.cut, 'cut', expectClipboardEvent));
       group('doubleClick', () => testEvent(Simulate.doubleClick, 'doubleClick', expectMouseEvent));
       group('drag', () => testEvent(Simulate.drag, 'drag', expectMouseEvent));

test/test_components.dart

@@ -16,6 +16,7 @@ class EventComponent extends Component {
         'onCompositionEnd': onEvent,
         'onCompositionStart': onEvent,
         'onCompositionUpdate': onEvent,
+        'onContextMenu': onEvent,
         'onCut': onEvent,
         'onDoubleClick': onEvent,
         'onDrag': onEvent,

test/test_components2.dart

@@ -16,6 +16,7 @@ class EventComponent2 extends Component2 {
         'onCompositionEnd': onEvent,
         'onCompositionStart': onEvent,
         'onCompositionUpdate': onEvent,
+        'onContextMenu': onEvent,
         'onCut': onEvent,
         'onDoubleClick': onEvent,
         'onDrag': onEvent,