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

tests/CanvasTest.cpp

Index: tests/CanvasTest.cpp
diff --git a/tests/CanvasTest.cpp b/tests/CanvasTest.cpp
index 70c2c04ffabf511239239fe8fe3cf91ab78582af..afbaf8650936d016b759de6368b7b389dd93726e 100644
--- a/tests/CanvasTest.cpp
+++ b/tests/CanvasTest.cpp
@@ -779,6 +779,27 @@ DEF_TEST(Canvas_ClipEmptyPath, reporter) {
     canvas.restore();
 }
 
+class SkTestCanvas : public SkCanvas {
+public:
+    void testUpdateDepth(skiatest::Reporter* reporter) {
+        // set some depths (with picture enabled), then check them as they get set
+
+        REPORTER_ASSERT(reporter, this->getZ() == 0);
+        this->translateZ(-10);
+        REPORTER_ASSERT(reporter, this->getZ() == -10);
+
+        this->save();
+        this->translateZ(20);
+        REPORTER_ASSERT(reporter, this->getZ() == 10);
+
+        this->restore();
+        REPORTER_ASSERT(reporter, this->getZ() == -10);
+
+        this->translateZ(13.14f);
+        REPORTER_ASSERT(reporter, SkScalarNearlyEqual(this->getZ(),3.14f));
+    }
+};
+
 namespace {
 
 class MockFilterCanvas : public SkPaintFilterCanvas {
@@ -812,4 +833,9 @@ DEF_TEST(PaintFilterCanvas_ConsistentState, reporter) {
     REPORTER_ASSERT(reporter, canvas.getTotalMatrix() == filterCanvas.getTotalMatrix());
     REPORTER_ASSERT(reporter, canvas.getClipBounds(&clip1) == filterCanvas.getClipBounds(&clip2));
     REPORTER_ASSERT(reporter, clip1 == clip2);
+
+    SkTestCanvas* tCanvas;
+
+    tCanvas = (SkTestCanvas*) new SkCanvas(100,100);
+    tCanvas->testUpdateDepth(reporter);
 }