Add filename to gradient scrape

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2160583002

Review-Url: https://codereview.chromium.org/2160583002
diff --git a/tools/lua/gradients.lua b/tools/lua/gradients.lua
index 2a14ff6..833b8b9 100644
--- a/tools/lua/gradients.lua
+++ b/tools/lua/gradients.lua
@@ -1,5 +1,12 @@
-function sk_scrape_startcanvas(c, fileName) end
-function sk_scrape_endcanvas(c, fileName) end
+filename = ""
+
+function sk_scrape_startcanvas(c, fileName)
+    filename = fileName
+end
+
+function sk_scrape_endcanvas(c, fileName)
+
+end
 
 LuaDoubleNearlyZero = 1.0 / bit32.lshift(1.0, 12)
 
@@ -27,6 +34,8 @@
 
                 gradients[i] = {}
 
+                gradients[i].filename = filename
+
                 gradients[i].colorCount = g.colorCount
                 gradients[i].type       = g.type
                 gradients[i].tile       = g.tile
@@ -70,7 +79,8 @@
             end
         end
 
-        io.write(string.format("%d %s %s %d %d %s %s\n",
+        io.write(string.format("%s %d %s %s %d %d %s %s\n",
+                                v.filename,
                                 v.colorCount,
                                 v.type,
                                 v.tile,
diff --git a/tools/lua/gradients.py b/tools/lua/gradients.py
index 0fa4c49..65ced5e 100755
--- a/tools/lua/gradients.py
+++ b/tools/lua/gradients.py
@@ -12,6 +12,7 @@
     with sqlite3.connect(outpath) as conn:
         c = conn.cursor();
         c.execute('''CREATE TABLE IF NOT EXISTS gradients (
+                        FileName      TEXT,
                         ColorCount    INTEGER,
                         GradientType  TEXT,
                         TileMode      TEXT,
@@ -27,8 +28,9 @@
             for line in [line.strip() for line in results]:
                 gradients.append(line.split());
 
-            c.executemany("INSERT INTO gradients VALUES (?, ?, ?, ?, ?, ?, ?)",
-                          gradients);
+            c.executemany(
+                "INSERT INTO gradients VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+                gradients);
 
             conn.commit();