[wv-supportlibrary] Expose dark mode API.

Bug: 952302
Change-Id: I3e6e37098db9e511c62d5b275b9f64e233f958e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1730917
Commit-Queue: Anna Malova <amalova@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697596}

android_webview/support_library/java/src/org/chromium/support_lib_glue/SupportLibWebViewChromiumFactory.java

@@ -71,7 +71,7 @@ class SupportLibWebViewChromiumFactory implements WebViewProviderFactoryBoundary
                     Features.TRACING_CONTROLLER_BASIC_USAGE,
                     Features.WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE,
                     Features.MULTI_PROCESS_QUERY,
-                    Features.FORCE_DARK + Features.DEV_SUFFIX,
+                    Features.FORCE_DARK,
             };
     // clang-format on