Add missing includes (flutter#6670)

Author: mehmetf

lib/ui/isolate_name_server/isolate_name_server_natives.h

@@ -5,6 +5,7 @@
 #ifndef FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_NATIVES_H_
 #define FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_NATIVES_H_
 
+#include <string>
 #include "third_party/dart/runtime/include/dart_api.h"
 
 namespace tonic {

lib/ui/text/asset_manager_font_provider.h

@@ -13,6 +13,7 @@
 #include "flutter/assets/asset_manager.h"
 #include "flutter/fml/macros.h"
 #include "third_party/skia/include/core/SkFontMgr.h"
+#include "third_party/skia/include/core/SkTypeface.h"
 #include "txt/font_asset_provider.h"
 
 namespace blink {

third_party/txt/src/minikin/GraphemeBreak.h

@@ -17,6 +17,9 @@
 #ifndef MINIKIN_GRAPHEME_BREAK_H
 #define MINIKIN_GRAPHEME_BREAK_H
 
+#include <stddef.h>
+#include <unicode/utf16.h>
+
 namespace minikin {
 
 class GraphemeBreak {