Decrease GrInOrderDrawBuffer::Cmd's reliance on GrInOrderDrawBuffer

include/core/SkChunkAlloc.h

Index: include/core/SkChunkAlloc.h
diff --git a/include/core/SkChunkAlloc.h b/include/core/SkChunkAlloc.h
index e13e2b99c640368ebfbdc5f3e16f6e47f3620807..56e4f06a17949ce89ee04eeadcec094a354dc380 100644
--- a/include/core/SkChunkAlloc.h
+++ b/include/core/SkChunkAlloc.h
@@ -22,12 +22,22 @@ public:
      *  pointers.
      */
     void reset();
+    /**
+     *  Free up all the blocks except the largest. This invalidates all
+     *  returned pointers.
+     */
+    void rewind();
 
     enum AllocFailType {
         kReturnNil_AllocFailType,
         kThrow_AllocFailType
     };
 
+    /**
+     *  Attempt to preallocate (but not mark as used) a block of memory
+     */
+    void preAlloc(size_t bytes);
+
     void* alloc(size_t bytes, AllocFailType);
     void* allocThrow(size_t bytes) {
         return this->alloc(bytes, kThrow_AllocFailType);
@@ -63,6 +73,8 @@ private:
     int     fBlockCount;
 
     Block* newBlock(size_t bytes, AllocFailType ftype);
+    Block* addBlockIfNecessary(size_t bytes, AllocFailType ftype);
+
 };
 
 #endif