Add internal Canvas save flags

Skia's SkCanvas::SaveFlags are being deprecated.  This CL introduces
the equivalent android::SaveFlags, converts all internal clients to
the new enum, and switches the saveLayer glue to the
SaveLayerRec-based API.

Change-Id: Icb1785f4e7c0f652b1f04b34a1e3ccb063c408f3
diff --git a/libs/hwui/Snapshot.cpp b/libs/hwui/Snapshot.cpp
index c6d8977..27fea1f 100644
--- a/libs/hwui/Snapshot.cpp
+++ b/libs/hwui/Snapshot.cpp
@@ -16,7 +16,7 @@
 
 #include "Snapshot.h"
 
-#include <SkCanvas.h>
+#include "Canvas.h"
 
 namespace android {
 namespace uirenderer {
@@ -57,14 +57,14 @@
         , mClipArea(nullptr)
         , mViewportData(s->mViewportData)
         , mRelativeLightCenter(s->mRelativeLightCenter) {
-    if (saveFlags & SkCanvas::kMatrix_SaveFlag) {
+    if (saveFlags & SaveFlags::Matrix) {
         mTransformRoot = *s->transform;
         transform = &mTransformRoot;
     } else {
         transform = s->transform;
     }
 
-    if (saveFlags & SkCanvas::kClip_SaveFlag) {
+    if (saveFlags & SaveFlags::Clip) {
         mClipAreaRoot = s->getClipArea();
         mClipArea = &mClipAreaRoot;
     } else {