Merge remote-tracking branch 'origin/tracking' into custom

gfx/thebes/gfxFont.cpp

@@ -860,6 +860,10 @@ gfxFont::gfxFont(gfxFontEntry *aFontEntry, const gfxFontStyle *aFontStyle,
     ++gFontCount;
 #endif
     mKerningSet = HasFeatureSet(HB_TAG('k','e','r','n'), mKerningEnabled);
+
+    // Ensure the gfxFontEntry's unitsPerEm and extents fields are initialized,
+    // so that GetFontExtents can use them without risk of races.
+    Unused << mFontEntry->UnitsPerEm();
 }
 
 gfxFont::~gfxFont()

gfx/thebes/gfxFontEntry.cpp

@@ -520,8 +520,9 @@ ShareTableAndGetBlob(nsTArray<uint8_t>&& aTable,
                            mSharedBlobData, DeleteFontTableBlobData);
     if (mBlob == hb_blob_get_empty() ) {
         // The FontTableBlobData was destroyed during hb_blob_create().
-        // The (empty) blob is still be held in the hashtable with a strong
+        // The (empty) blob will still be held in the hashtable with a strong
         // reference.
+        mSharedBlobData = nullptr;
         return hb_blob_reference(mBlob);
     }