Added 3-color gradient scraper for detecting symmetrical gradients.

src/utils/SkLua.cpp

Index: src/utils/SkLua.cpp
diff --git a/src/utils/SkLua.cpp b/src/utils/SkLua.cpp
index 66a9c08597188ceaedcc21a105b249d4ab10ffd6..8267132b2f98ef073f0b49dd7f02ca127943ce82 100644
--- a/src/utils/SkLua.cpp
+++ b/src/utils/SkLua.cpp
@@ -712,12 +712,26 @@ static int lshader_asAGradient(lua_State* L) {
     if (shader) {
         SkShader::GradientInfo info;
         sk_bzero(&info, sizeof(info));
+
+        SkColor colors[3];  // hacked in for extracting info on 3 color case.
+        SkScalar pos[3];    
+
+        info.fColorCount = 3;
+        info.fColors = &colors[0];
+        info.fColorOffsets = &pos[0];
+        
         SkShader::GradientType t = shader->asAGradient(&info);
+
         if (SkShader::kNone_GradientType != t) {
             lua_newtable(L);
             setfield_string(L, "type", gradtype2string(t));
             setfield_number(L, "colorCount", info.fColorCount);
             setfield_string(L, "tile", mode2string(info.fTileMode));
+
+            if (info.fColorCount == 3){

[reed1, 2013/08/01 16:23:26]

nit: 3 == info.fColorCount

This ordering ensures you can't accidentally type 3 = info.fColorCount, which
would be assigning to a literal.

+                setfield_number(L, "midPos", pos[1]);
+            }
+            
             return 1;
         }
     }