Currently, `WebPage` has already a public `setBackgroundColor()` method, but the class is not public. Therefore, public API is needed in `WebView` to allow developers access to it.
In line with the `fontSmoothingType` property, this PR provides public support for setting the background color of a WebPage, by adding a `pageFill` property, and a CSR is required. The color for the background, that can be opaque, transparent or with any level of opacity, can be set via code or via CSS using `-fx-page-fill`. Unit tests and a system test are provided. ------------- Commit messages: - Support webView transparency (#1) Changes: https://git.openjdk.java.net/jfx/pull/563/files Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=563&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8090547 Stats: 482 lines in 8 files changed: 468 ins; 1 del; 13 mod Patch: https://git.openjdk.java.net/jfx/pull/563.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/563/head:pull/563 PR: https://git.openjdk.java.net/jfx/pull/563
