Simplify storage of MC State stack

src/core/SkMatrixClipStateMgr.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkMatrixClipStateMgr_DEFINED
 #define SkMatrixClipStateMgr_DEFINED
 
 #include "SkCanvas.h"
@@ skipping 35 matching lines @@
 
 // The SkMatrixClipStateMgr works by intercepting all the save*, restore, clip*,
 // and matrix calls sent to SkCanvas in order to track the current matrix/clip
 // state. All the other canvas calls get funnelled into a generic "call" entry
 // point that signals that a state block is required.
 class SkMatrixClipStateMgr {
 public:
     static const int32_t kIdentityWideOpenStateID = 0;
     static const int kIdentityMatID = 0;
 
-    class MatrixClipState {
+    class MatrixClipState : public SkNoncopyable {
     public:
         class MatrixInfo {
         public:
             void reset() {
                 fMatrixID = kIdentityMatID;
                 fMatrix.reset();
             }
 
             bool preTranslate(SkScalar dx, SkScalar dy) {
                 fMatrixID = -1;
@@ skipping 30 matching lines @@
                     return fMatrixID;
                 }
 
                 fMatrixID = mgr->addMatToDict(fMatrix);
                 return fMatrixID;
             }
 
         private:
             SkMatrix fMatrix;
             int      fMatrixID;
+
+            typedef SkNoncopyable INHERITED;
         };
 
         class ClipInfo : public SkNoncopyable {
         public:
             ClipInfo() {}
 
             bool clipRect(const SkRect& rect,
                           SkRegion::Op op,
                           bool doAA,
                           int matrixID) {
@@ skipping 38 matching lines @@
                 kRRect_ClipType,
                 kPath_ClipType,
                 kRegion_ClipType
             };
 
             class ClipOp {
             public:
                 ClipType     fClipType;
 
                 union {
-                    SkRRect fRRect;        // also stores clipRect
+                    SkRRect fRRect;        // also stores clip rect
                     int     fPathID;
                     int     fRegionID;
                 } fGeom;
 
                 bool         fDoAA;
                 SkRegion::Op fOp;
 
                 // The CTM in effect when this clip call was issued
                 int          fMatrixID;
             };
@@ skipping 53 matching lines @@
         MatrixInfo   fMatrixInfoStorage;
 
         ClipInfo*    fClipInfo;
         ClipInfo     fClipInfoStorage;
 
         // Tracks the current depth of saveLayers to support the isDrawingToLayer call
         int          fLayerID;
         // Does this MC state represent a saveLayer call?
         bool         fIsSaveLayer;
 
-        // The next two fields are only valid when fIsSaveLayer is set.
-        int32_t      fSaveLayerBaseStateID;
+        // The next field is only valid when fIsSaveLayer is set.
         SkTDArray<int>* fSavedSkipOffsets;
 
         // Does the MC state have an open block in the skp?
         bool         fHasOpen;
 
         MatrixClipState* fPrev;
 
 #ifdef SK_DEBUG
         int              fExpectedDepth;    // debugging aid
 #endif
@@ skipping 141 matching lines @@
     }
 
     // TODO: add stats to check if the dictionary really does
     // reduce the size of the SkPicture.
     int addMatToDict(const SkMatrix& mat);
     const SkMatrix& lookupMat(int index) {
         SkASSERT(index >= 0 && index < fMatrixDict.count());
         return fMatrixDict[index];
     }
 
-    bool isCurrentlyOpen(int32_t stateID);
+    bool isNestingMCState(int stateID);
 
 #ifdef SK_DEBUG
     int fActualDepth;
 #endif
+
+    // save layers are nested within a specific MC state. This stack tracks
+    // the nesting MC state's ID as save layers are pushed and popped.
+    SkTDArray<int> fStateIDStack;
 };
 
 #endif