[DO NOT COMMIT] Trace events for layout-based First Meaningful Paint detection

third_party/WebKit/Source/core/css/FontFaceSet.h

Index: third_party/WebKit/Source/core/css/FontFaceSet.h
diff --git a/third_party/WebKit/Source/core/css/FontFaceSet.h b/third_party/WebKit/Source/core/css/FontFaceSet.h
index a74525545a275f426c880a68e0a0e30c3d2a5119..3780d1c57cbbabd101740b9cb8dc5937145e08a7 100644
--- a/third_party/WebKit/Source/core/css/FontFaceSet.h
+++ b/third_party/WebKit/Source/core/css/FontFaceSet.h
@@ -89,6 +89,8 @@ public:
     void fontLoaded(FontFace*);
     void loadError(FontFace*);
 
+    bool hasBlankText() const;
+
     // ActiveDOMObject
     void suspend() override;
     void resume() override;
@@ -96,6 +98,7 @@ public:
 
     static FontFaceSet* from(Document&);
     static void didLayout(Document&);
+    static bool hasBlankText(Document&);
 
     void addFontFacesToFontFaceCache(FontFaceCache*, CSSFontSelector*);