Bug 306244 – Fix -Wlifetime-safety-permissive warning in FontRanges::glyphDataForCharacter()

• Status: RESOLVED
• Resolution: FIXED
• Component: Text

[David Kilzer (:ddkilzer)]

Clang's lifetime safety warning detected a potential issue in FontRanges::glyphDataForCharacter():

```
OpenSource/Source/WebCore/platform/graphics/FontRanges.cpp:94:38: error: object whose reference is captured may not live long enough [-Werror,-Wlifetime-safety-strict]
   94 |                         resultFont = font.get();
      |                                      ^~~~
OpenSource/Source/WebCore/platform/graphics/FontRanges.cpp:104:13: note: destroyed here
  104 |             }
      |             ^
OpenSource/Source/WebCore/platform/graphics/FontRanges.cpp:93:26: note: later used here
   93 |                     if (\!resultFont)
      |                          ^~~~~~~~~~
```

Even though the code was safe (the Font is kept alive by the FontAccessor), the analyzer couldn't prove the lifetime relationship.

[David Kilzer (:ddkilzer)]

The fix changes `resultFont` from `const Font*` to `RefPtr<const Font>` to make the lifetime relationship explicit and eliminate the warning. Also uses `WTF::move(font)` to avoid ref count churn since `font` isn't used after that point in the `isInterstitial()` branch.

No change in behavior, only compiler warning elimination.

[Radar WebKit Bug Importer]

<rdar://problem/168892583>

[Radar WebKit Bug Importer]

<rdar://problem/168892499>

[David Kilzer (:ddkilzer)]

Pull request: https://github.com/WebKit/WebKit/pull/57231

[EWS]

Committed 306238@main (3118028cc9ac): <https://commits.webkit.org/306238@main>

Reviewed commits have been landed. Closing PR #57231 and removing active labels.