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

src/core/SkCanvas.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
 #include "SkCanvasPriv.h"
@@ skipping 1503 matching lines @@
 void SkCanvas::setMatrix(const SkMatrix& matrix) {
     this->checkForDeferredSave();
     this->internalSetMatrix(matrix);
     this->didSetMatrix(matrix);
 }
 
 void SkCanvas::resetMatrix() {
     this->setMatrix(SkMatrix::I());
 }
 
+void SkCanvas::setZ(uint32_t z) {

[jvanverth1, 2016/07/07 18:43:02]

This and getZ() could be inlined directly in the SkCanvas class declaration in
SkCanvas.h

[vjiaoblack, 2016/07/07 19:04:10]

Done.

+    this->curDrawDepth = z;
+    this->didSetZ(z);
+}
+
+uint32_t SkCanvas::getZ() const {
+    return this->curDrawDepth;
+}
+
 //////////////////////////////////////////////////////////////////////////////
 
 void SkCanvas::clipRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
     if (!fAllowSoftClip) {
         doAA = false;
     }
 
 #ifdef SK_SUPPORT_PRECHECK_CLIPRECT
     // Check if we can quick-accept the clip call (and do nothing)
     //
@@ skipping 1560 matching lines @@
 
 SkAutoCanvasMatrixPaint::~SkAutoCanvasMatrixPaint() {
     fCanvas->restoreToCount(fSaveCount);
 }
 
 #ifdef SK_SUPPORT_LEGACY_NEW_SURFACE_API
 SkSurface* SkCanvas::newSurface(const SkImageInfo& info, const SkSurfaceProps* props) {
     return this->makeSurface(info, props).release();
 }
 #endif