Added the framework for having canvas/recorder/picture record depth_set's.

tools/debugger/SkDrawCommand.h

Index: tools/debugger/SkDrawCommand.h
diff --git a/tools/debugger/SkDrawCommand.h b/tools/debugger/SkDrawCommand.h
index 8b8ada267fa8845f1fa243f60bfe205f8891715b..0414dbff7afb464f2e59072d3a88d6f0367f6451 100644
--- a/tools/debugger/SkDrawCommand.h
+++ b/tools/debugger/SkDrawCommand.h
@@ -54,8 +54,9 @@ public:
         kSave_OpType,
         kSaveLayer_OpType,
         kSetMatrix_OpType,
+        kTranslateZ_OpType,
 
-        kLast_OpType = kSetMatrix_OpType
+        kLast_OpType = kTranslateZ_OpType
     };
 
     static const int kOpTypeCount = kLast_OpType + 1;
@@ -123,6 +124,7 @@ public:
     static Json::Value MakeJsonRect(const SkRect& rect);
     static Json::Value MakeJsonIRect(const SkIRect&);
     static Json::Value MakeJsonMatrix(const SkMatrix&);
+    static Json::Value MakeJsonScalar(SkScalar);
     static Json::Value MakeJsonPath(const SkPath& path);
     static Json::Value MakeJsonRegion(const SkRegion& region);
     static Json::Value MakeJsonPaint(const SkPaint& paint, UrlDataManager& urlDataManager);
@@ -709,4 +711,16 @@ private:
     typedef SkDrawCommand INHERITED;
 };
 
+class SkTranslateZCommand : public SkDrawCommand {
+public:
+    SkTranslateZCommand(SkScalar);
+    void execute(SkCanvas* canvas) const override;
+    Json::Value toJSON(UrlDataManager& urlDataManager) const override;
+    static SkTranslateZCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
+
+private:
+    SkScalar fZTranslate;
+
+    typedef SkDrawCommand INHERITED;
+};
 #endif