[8u] RFR 8209113: Use WeakReference for lastFontStrike for created Fonts

[Hohensee, Paul]

Lgtm, except there's an over-indentation issue in the 2nd hunk for Font2D.java.

Paul 

On 3/20/20, 3:02 PM, "jdk8u-dev on behalf of Zhengyu Gu" <jdk8u-dev-bounces at openjdk.java.net on behalf of zgu at redhat.com> wrote:
    
    Hi,
    
    I would like to backport this change to JDK8u. This patch fixes a memory
    leak that can be reproduced in 8u.
    
    The original patch does not apply cleanly. Other than location mismatch,
    I changed
    FontStrikeDisposer.strikeCache type in original patch
    ConcurrentHashMap<FontStrikeDesc, Reference<FontStrike>> =>
    ConcurrentHashMap<FontStrikeDesc, Reference>
    to match Font2D.strikeCache
    
    Original bug: https://bugs.openjdk.java.net/browse/JDK-8209113
    Original code review thread:
    https://mail.openjdk.java.net/pipermail/2d-dev/2019-December/010470.html
    
    
    8u Webrev:
    http://cr.openjdk.java.net/~zgu/JDK-8209113-8u/webrev.00/index.html
    
    Test:
       The testcase in bug.
    
    Thanks,
    
    -Zhengyu