Modify skpdiff to write diffs directly to provided directories

tools/skpdiff/skpdiff_main.cpp

Index: tools/skpdiff/skpdiff_main.cpp
diff --git a/tools/skpdiff/skpdiff_main.cpp b/tools/skpdiff/skpdiff_main.cpp
index 3d1bcda0f475159b3c36c203ffa0487c8dac4658..6c40552d334b79b4cffb59d114d60d58a0fd507c 100644
--- a/tools/skpdiff/skpdiff_main.cpp
+++ b/tools/skpdiff/skpdiff_main.cpp
@@ -49,6 +49,7 @@ DEFINE_string(whiteDiffDir, "", "If the differ can generate an image showing eve
 DEFINE_bool(jsonp, true, "Output JSON with padding");
 DEFINE_string(csv, "", "Writes the output of these diffs to a csv file: <filepath>");
 DEFINE_int32(threads, -1, "run N threads in parallel [default is derived from CPUs available]");
+DEFINE_bool(longnames, false, "Output image names are a combination of baseline and test names");
 
 #if SK_SUPPORT_OPENCL
 /// A callback for any OpenCL errors
@@ -206,6 +207,7 @@ int tool_main(int argc, char * argv[]) {
             return 1;
         }
     }
+
     if (!FLAGS_whiteDiffDir.isEmpty()) {
         if (1 != FLAGS_whiteDiffDir.count()) {
             SkDebugf("whiteDiffDir flag expects one argument: <directory>\n");
@@ -215,6 +217,7 @@ int tool_main(int argc, char * argv[]) {
 
     SkDiffContext ctx;
     ctx.setDiffers(chosenDiffers);
+    ctx.setLongNames(FLAGS_longnames);
 
     if (!FLAGS_alphaDir.isEmpty()) {
         ctx.setAlphaMaskDir(SkString(FLAGS_alphaDir[0]));