[FreeType] Problem under WebCore::FontPlatformData::FontPlatformData

https://bugs.webkit.org/show_bug.cgi?id=191595

Unofficially reviewed stable branch commit.

Blacklist cairo 1.15 and 1.16.0 when setting FreeType memory allocation functions. These
broken versions of cairo free memory allocated by FreeType with system free. We can avoid
trouble by using the system allocator instead of bmalloc.

* platform/graphics/freetype/FontCustomPlatformDataFreeType.cpp:
(WebCore::initializeFreeTypeLibrary):

Source/WebCore/ChangeLog

@@ -1,3 +1,17 @@
+2018-11-21  Michael Catanzaro  <mcatanzaro@igalia.com>
+
+        [FreeType] Problem under WebCore::FontPlatformData::FontPlatformData
+        https://bugs.webkit.org/show_bug.cgi?id=191595
+
+        Unofficially reviewed stable branch commit.
+
+        Blacklist cairo 1.15 and 1.16.0 when setting FreeType memory allocation functions. These
+        broken versions of cairo free memory allocated by FreeType with system free. We can avoid
+        trouble by using the system allocator instead of bmalloc.
+
+        * platform/graphics/freetype/FontCustomPlatformDataFreeType.cpp:
+        (WebCore::initializeFreeTypeLibrary):
+
 2018-11-20  Zan Dobersek  <zdobersek@igalia.com>
 
         Segfaults on https://terminalizer.com/

Source/WebCore/platform/graphics/freetype/FontCustomPlatformDataFreeType.cpp

@@ -66,6 +66,13 @@ static bool initializeFreeTypeLibrary(FT_Library& library)
     // https://www.freetype.org/freetype2/docs/design/design-4.html
     // https://lists.nongnu.org/archive/html/freetype-devel/2004-10/msg00022.html
 
+    // Workaround crash in cairo 1.16.0. See https://webkit.org/b/191595.
+    int version = cairo_version();
+    if (version >= CAIRO_VERSION_ENCODE(1, 15, 0) && version < CAIRO_VERSION_ENCODE(1, 16, 1)) {
+        FT_Init_FreeType(&library);
+        return true;
+    }
+
     FT_Memory memory = bitwise_cast<FT_Memory>(ft_smalloc(sizeof(*memory)));
     if (!memory)
         return false;