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

src/core/SkPictureRecord.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPictureRecord.h"
 #include "SkImage_Base.h"
 #include "SkPatchUtils.h"
@@ skipping 200 matching lines @@
 void SkPictureRecord::didSetMatrix(const SkMatrix& matrix) {
     this->validate(fWriter.bytesWritten(), 0);
     // op + matrix
     size_t size = kUInt32Size + matrix.writeToMemory(nullptr);
     size_t initialOffset = this->addDraw(SET_MATRIX, &size);
     this->addMatrix(matrix);
     this->validate(initialOffset, size);
     this->INHERITED::didSetMatrix(matrix);
 }
 
+void SkPictureRecord::didSetZ(const SkScalar z) {
+    this->validate(fWriter.bytesWritten(), 0);
+    // set Z
+    size_t size = sizeof(SkScalar);
+    size_t initialOffset = this->addDraw(SET_Z, &size);
+
+    this->validate(initialOffset, size);
+}
+
 static bool regionOpExpands(SkRegion::Op op) {
     switch (op) {
         case SkRegion::kUnion_Op:
         case SkRegion::kXOR_Op:
         case SkRegion::kReverseDifference_Op:
         case SkRegion::kReplace_Op:
             return true;
         case SkRegion::kIntersect_Op:
         case SkRegion::kDifference_Op:
             return false;
@@ skipping 765 matching lines @@
 
 void SkPictureRecord::addTextBlob(const SkTextBlob *blob) {
     int index = fTextBlobRefs.count();
     *fTextBlobRefs.append() = blob;
     blob->ref();
     // follow the convention of recording a 1-based index
     this->addInt(index + 1);
 }
 
 ///////////////////////////////////////////////////////////////////////////////