RFR: 8218973: SVG with masking is not rendering image with mask effect

[Bhawesh Choudhary]

Root cause of issue is Specifying a image mask from GraphicsContextJava.cpp in WebKit was not implemented, so masking
doesn't take place at all while rendering SVGRect. to fix this issue add implementation of function clipToImageBuffer()
in GraphicsContextJava.cpp and send clip image to WCGraphicsPrismContext.java  While rendering in
WCGraphicsPrismContext.java if image clip mask is available, use it for rendering using MaskTextureGraphics interface
otherwise use usual way of rendering.

-------------

Commit messages:
 - Formatting correction (Line Endings)
 - removed executable file mode
 - Added unit test + SW Graphics rendering part
 - Pixel scale issue fix
 - 8218973: SVG with masking is not rendering image with mask effect

Changes: https://git.openjdk.java.net/jfx/pull/213/files
 Webrev: https://webrevs.openjdk.java.net/jfx/213/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8218973
  Stats: 132 lines in 6 files changed: 130 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jfx/pull/213.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/213/head:pull/213

PR: https://git.openjdk.java.net/jfx/pull/213