add textblobs to lua

include/utils/SkTextBox.h

Index: include/utils/SkTextBox.h
diff --git a/include/utils/SkTextBox.h b/include/utils/SkTextBox.h
index e217076fed4a8eee43fa9dea698471de3e7f05a8..d4372d1b6ab8f0d07fdb5991f9fc840774413385 100644
--- a/include/utils/SkTextBox.h
+++ b/include/utils/SkTextBox.h
@@ -60,6 +60,14 @@ public:
     int     countLines() const;
     SkScalar getTextHeight() const;
 
+    SkTextBlob* snapshotTextBlob(SkScalar* computedBottom) const;
+
+    class Visitor {
+    public:
+        virtual ~Visitor() {}
+        virtual void operator()(const char*, size_t, SkScalar x, SkScalar y, const SkPaint&) = 0;
+    };
+    
 private:
     SkRect      fBox;
     SkScalar    fSpacingMul, fSpacingAdd;
@@ -67,6 +75,8 @@ private:
     const char* fText;
     size_t      fLen;
     const SkPaint* fPaint;
+
+    SkScalar visit(Visitor&, const char text[], size_t len, const SkPaint&) const;
 };
 
 class SkTextLineBreaker {