Add clip to layer cache

src/gpu/GrPictureUtils.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 GrPictureUtils_DEFINED
 #define GrPictureUtils_DEFINED
 
 #include "SkPicture.h"
 #include "SkTArray.h"
 
 // This class encapsulates the GPU-backend-specific acceleration data
 // for a single SkPicture
 class GrAccelData : public SkPicture::AccelData {
 public:
     // Information about a given saveLayer in an SkPicture
     class SaveLayerInfo {
     public:
         SaveLayerInfo() : fPicture(NULL), fPaint(NULL) {}
         ~SaveLayerInfo() { SkSafeUnref(fPicture); SkDELETE(fPaint); }
 
         // The picture owning the layer. If the owning picture is the top-most
         // one (i.e., the picture for which this GrAccelData was created) then
         // this pointer is NULL. If it is a nested picture then the pointer
         // is non-NULL and owns a ref on the picture.
         const SkPicture* fPicture;
-        // The size of the saveLayer
-        SkISize fSize;
+        // The device space bounds of this layer.
+        SkIRect fBounds;
         // The matrix state in which this layer's draws must occur. It does not
         // include the translation needed to map the layer's top-left point to the origin.
         SkMatrix fOriginXform;
-        // The offset that needs to be passed to drawBitmap to correctly
-        // position the pre-rendered layer. It is in device space.
-        SkIPoint fOffset;
         // The paint to use on restore. Can be NULL since it is optional.
         const SkPaint* fPaint;
         // The ID of this saveLayer in the picture. 0 is an invalid ID.
         size_t  fSaveLayerOpID;
         // The ID of the matching restore in the picture. 0 is an invalid ID.
         size_t  fRestoreOpID;
         // True if this saveLayer has at least one other saveLayer nested within it.
         // False otherwise.
         bool    fHasNestedLayers;
         // True if this saveLayer is nested within another. False otherwise.
@@ skipping 20 matching lines @@
 
 private:
     SkTArray<SaveLayerInfo, true> fSaveLayerInfo;
 
     typedef SkPicture::AccelData INHERITED;
 };
 
 const GrAccelData* GPUOptimize(const SkPicture* pict);
 
 #endif // GrPictureUtils_DEFINED