Infrastructure changes to support pull saveLayers forward task

src/gpu/GrPictureUtils.h

Index: src/gpu/GrPictureUtils.h
===================================================================
--- src/gpu/GrPictureUtils.h	(revision 14579)
+++ src/gpu/GrPictureUtils.h	(working copy)
@@ -17,8 +17,21 @@
 public:
     // Information about a given saveLayer in an SkPicture
     struct SaveLayerInfo {
+        // True if the SaveLayerInfo is valid. False if either 'fOffset' is
+        // invalid (due to a non-invertible CTM) or 'fPaint' is NULL (due
+        // to a non-copyable paint).
+        bool fValid;
         // The size of the saveLayer
         SkISize fSize;
+        // The CTM in which this layer's draws must occur. It already incorporates
+        // the translation needed to map the layer's top-left point to the origin.
+        SkMatrix fCTM;
+        // The offset that needs to be passed to drawBitmap to correctly
+        // position the pre-rendered layer.
+        SkPoint fOffset;
+        // The paint to use on restore. NULL if the paint was not copyable (and
+        // thus that this layer should not be pulled forward).
+        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.
@@ -26,6 +39,8 @@
         // 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.
+        bool    fIsNested;
     };
 
     GPUAccelData(Key key) : INHERITED(key) { }
@@ -43,6 +58,10 @@
         return fSaveLayerInfo[index];
     }
 
+    // We may, in the future, need to pass in the GPUDevice in order to
+    // incorporate the clip and matrix state into the key
+    static SkPicture::AccelData::Key ComputeAccelDataKey();
+
 protected:
     SkTDArray<SaveLayerInfo> fSaveLayerInfo;