Add cull rect visualization to debugger

src/utils/debugger/SkDrawCommand.cpp

Index: src/utils/debugger/SkDrawCommand.cpp
===================================================================
--- src/utils/debugger/SkDrawCommand.cpp	(revision 13645)
+++ src/utils/debugger/SkDrawCommand.cpp	(working copy)
@@ -885,6 +885,10 @@
                       fFlags);
 }
 
+void SkSaveLayerCommand::vizExecute(SkCanvas* canvas) {
+    canvas->save();
+}
+
 void SkSaveLayerCommand::trackSaveState(int* state) {
     (*state)++;
 }
@@ -946,10 +950,18 @@
 }
 
 void SkPushCullCommand::execute(SkCanvas* canvas) {
-    //FIXME: add visualization overlay.
     canvas->pushCull(fCullRect);
 }
 
+void SkPushCullCommand::vizExecute(SkCanvas* canvas) {
+    canvas->pushCull(fCullRect);
+
+    SkPaint p;
+    p.setColor(SK_ColorCYAN);
+    p.setStyle(SkPaint::kStroke_Style);
+    canvas->drawRect(fCullRect, p);
+}
+
 SkPopCullCommand::SkPopCullCommand() {
     fDrawType = POP_CULL;
 }