Optimize CSS box-shadow performance by caching the SkMask of the blur effect.

include/core/SkMask.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkMask_DEFINED
 #define SkMask_DEFINED
 
+#include "SkDiscardableMemory.h"
 #include "SkRect.h"
 
 /** \class SkMask
     SkMask is used to describe alpha bitmaps, either 1bit, 8bit, or
     the 3-channel 3D format. These are passed to SkMaskFilter objects.
 */
 struct SkMask {
     enum Format {
         kBW_Format, //!< 1bit per pixel mask (e.g. monochrome)
         kA8_Format, //!< 8bits per pixel mask (e.g. antialiasing)
         k3D_Format, //!< 3 8bit per pixl planes: alpha, mul, add
         kARGB32_Format,         //!< SkPMColor
         kLCD16_Format,          //!< 565 alpha for r/g/b
         kLCD32_Format           //!< 888 alpha for r/g/b
     };
 
     enum {
         kCountMaskFormats = kLCD32_Format + 1
     };
 
+    SkDiscardableMemory* fDiscardableMemory;
+    bool fUseDiscardableMemory;
     uint8_t*    fImage;
     SkIRect     fBounds;
     uint32_t    fRowBytes;
     Format      fFormat;
 
     /** Returns true if the mask is empty: i.e. it has an empty bounds.
      */
     bool isEmpty() const { return fBounds.isEmpty(); }
 
     /** Return the byte size of the mask, assuming only 1 plane.
@@ skipping 110 matching lines @@
     ~SkAutoMaskFreeImage() {
         SkMask::FreeImage(fImage);
     }
 
 private:
     uint8_t* fImage;
 };
 #define SkAutoMaskFreeImage(...) SK_REQUIRE_LOCAL_VAR(SkAutoMaskFreeImage)
 
 #endif