Make HarfBuzzFace release SimpleFontData.

third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.h

Index: third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.h
diff --git a/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.h b/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.h
index c2575b43db207a58b2e89e641f5d6b3d7c9c7d7a..98021356f79e9b02473aff66d4512dd0abcfc086 100644
--- a/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.h
+++ b/third_party/WebKit/Source/platform/fonts/shaping/HarfBuzzFace.h
@@ -70,6 +70,7 @@ class HarfBuzzFace : public RefCounted<HarfBuzzFace> {
 
   FontPlatformData* m_platformData;
   uint64_t m_uniqueID;
+  mutable class SimpleFontData* m_simpleFontData;

[drott, 2016/10/11 11:40:44]

Because of the way the caching works in this class, I'd prefer to avoid
additional storage in HarfBuzzFace itself for pointers to SimpleFontData or
FontPlatformData. As much as possible should be in HarfBuzzFontData since these
we have a lot fewer of those. SimpleFontData objects actually keep a copy of
FontPlatformData objects, so this would be redundantly storing the same
FontPlatformData inside the m_simpleFontData.

A longer term consideration might be, whether we should hang HarfBuzzFace off of
SimpleFontData or make the main m_platformData maybe a m_simpleFontData.

   hb_font_t* m_unscaledFont;
   HarfBuzzFontData* m_harfBuzzFontData;
 };