Add changelog for custom nav menu header register

+ tests

Signed-off-by: Yulong Ruan <ruanyl@amazon.com>

CHANGELOG.md

@@ -40,6 +40,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - [Theme] Use themes' definitions to render the initial view ([#4936](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/4936))
 - [Theme] Make `next` theme the default ([#4854](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/4854))
 - [Discover] Update embeddable for saved searches ([#5081](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5081))
+- [Chrome] Introduce registerCollapsibleNavHeader to allow plugins to customize the rendering of nav menu header ([#5244](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5244))
 
 ### 🐛 Bug Fixes
 
@@ -797,4 +798,4 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### 🔩 Tests
 
-- Update caniuse to fix failed integration tests ([#2322](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/2322))
+- Update caniuse to fix failed integration tests ([#2322](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/2322))

src/core/public/chrome/chrome_service.test.ts

@@ -105,6 +105,22 @@ afterAll(() => {
   (window as any).localStorage = originalLocalStorage;
 });
 
+describe('setup', () => {
+  it('register custom Nav Header render', async () => {
+    const customHeaderMock = React.createElement('TestCustomNavHeader');
+    const renderMock = jest.fn().mockReturnValue(customHeaderMock);
+    const chrome = new ChromeService({ browserSupportsCsp: true });
+
+    const chromeSetup = chrome.setup();
+    chromeSetup.registerCollapsibleNavHeader(renderMock);
+
+    const chromeStart = await chrome.start(defaultStartDeps());
+    const wrapper = shallow(React.createElement(() => chromeStart.getHeaderComponent()));
+    expect(wrapper.prop('collapsibleNavHeaderRender')).toBeDefined();
+    expect(wrapper.prop('collapsibleNavHeaderRender')()).toEqual(customHeaderMock);
+  });
+});
+
 describe('start', () => {
   it('adds legacy browser warning if browserSupportsCsp is disabled and warnLegacyBrowsers is enabled', async () => {
     const { startDeps } = await start({ options: { browserSupportsCsp: false } });