RFR: 8015854: [macosx] JButton's HTML ImageView adding unwanted padding [v8]

[DamonGuy]

> Html does not fit in JButton at certain sizes because default Insets cause html to be displayed off-center. 
> 
> Changes made to SwingUtilities.java layoutCompoundLabelImpl method to enable clipping if html does not fit, similar to regular text. AquaButtonUI.java now detects when html does not fit, and an implementation for alternate insets that are recursively tested for regular text inside layoutAndGetText() are now also being used for html content.
> 
> Created test (Bug8015854.java) with the same format as the test described on the issue. The button is of size 37x37 with an image of a red square sized 19x19. The test checks for red pixels on the edges of where the square image should be from the center of the button. The test fails with the non-changed jdk, but passes with the changes.

DamonGuy has updated the pull request incrementally with one additional commit since the last revision:

  Updated test to be headless using BufferedImage.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7310/files
  - new: https://git.openjdk.java.net/jdk/pull/7310/files/d9db4c2b..dd8599ce

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7310&range=07
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7310&range=06-07

  Stats: 113 lines in 1 file changed: 13 ins; 57 del; 43 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7310.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7310/head:pull/7310

PR: https://git.openjdk.java.net/jdk/pull/7310