add explicit filepaths to render_pictures JSON summary

tools/PictureRenderer.h

Index: tools/PictureRenderer.h
diff --git a/tools/PictureRenderer.h b/tools/PictureRenderer.h
index 7c5a9da1f0d2d97f6cb26d02b5edafc8e4f712f5..5a8b71478f64d9c7c7613baf35e91971665c03ae 100644
--- a/tools/PictureRenderer.h
+++ b/tools/PictureRenderer.h
@@ -47,17 +47,19 @@ public:
      * Adds this bitmap hash to the summary of results.
      *
      * @param testName name of the test
+     * @param fileName relative path to the image output file on local disk
      * @param hash hash to store
      */
-    void add(const char *testName, uint64_t hash);
+    void add(const char *testName, const char *fileName, uint64_t hash);
 
     /**
      * Adds this bitmap's hash to the summary of results.
      *
      * @param testName name of the test
+     * @param fileName relative path to the image output file on local disk
      * @param bitmap bitmap to store the hash of
      */
-    void add(const char *testName, const SkBitmap& bitmap);
+    void add(const char *testName, const char *fileName, const SkBitmap& bitmap);
 
     /**
      * Writes the summary (as constructed so far) to a file.