As mentioned in JBS, the `clearQuad` methods in `D3DGraphics` and `ES2Graphics` are now identical, which should have been the case all along. The fact that they weren't identical was the source of a bug that was only discovered during the testing of [JDK-8090547](https://bugs.openjdk.java.net/browse/JDK-8090547) on the es2 pipeline.
This PR moves the `clearQuad` method to the `BaseShaderGraphics` superclass to get rid of the unnecessary code duplication. This will be helpful when implementing the metal pipeline as well. As a note, I made the `context` field in the `D3DGraphics` final, which it should have been. This is necessary to ensure that moving the method to the super-class is equivalent. No new tests are needed, since this is just refactoring. ------------- Commit messages: - 8273946: Move clearQuad method to BaseShaderGraphics superclass Changes: https://git.openjdk.java.net/jfx/pull/628/files Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=628&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8273946 Stats: 59 lines in 3 files changed: 18 ins; 40 del; 1 mod Patch: https://git.openjdk.java.net/jfx/pull/628.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/628/head:pull/628 PR: https://git.openjdk.java.net/jfx/pull/628
