change signature for virtual related to saveLayer, passing SaveLayerRec

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1533953002

NOTREECHECKS=True

Review URL: https://codereview.chromium.org/1533953002
diff --git a/src/utils/SkDumpCanvas.cpp b/src/utils/SkDumpCanvas.cpp
index a500561..916c32a 100644
--- a/src/utils/SkDumpCanvas.cpp
+++ b/src/utils/SkDumpCanvas.cpp
@@ -199,14 +199,14 @@
     this->INHERITED::willSave();
 }
 
-SkCanvas::SaveLayerStrategy SkDumpCanvas::willSaveLayer(const SkRect* bounds, const SkPaint* paint,
-                                                        SaveFlags flags) {
+SkCanvas::SaveLayerStrategy SkDumpCanvas::getSaveLayerStrategy(const SaveLayerRec& rec) {
     SkString str;
-    str.printf("saveLayer(0x%X)", flags);
-    if (bounds) {
+    str.printf("saveLayer(0x%X)", rec.fSaveLayerFlags);
+    if (rec.fBounds) {
         str.append(" bounds");
-        toString(*bounds, &str);
+        toString(*rec.fBounds, &str);
     }
+    const SkPaint* paint = rec.fPaint;
     if (paint) {
         if (paint->getAlpha() != 0xFF) {
             str.appendf(" alpha:0x%02X", paint->getAlpha());
@@ -216,7 +216,7 @@
         }
     }
     this->dump(kSave_Verb, paint, str.c_str());
-    return this->INHERITED::willSaveLayer(bounds, paint, flags);
+    return this->INHERITED::getSaveLayerStrategy(rec);
 }
 
 void SkDumpCanvas::willRestore() {