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

src/core/SkMaskFilter.cpp

Index: src/core/SkMaskFilter.cpp
diff --git a/src/core/SkMaskFilter.cpp b/src/core/SkMaskFilter.cpp
index 2ab2843641a03580e698023af9b4ae05219178fb..6f9007d7d28a75e515bae5de84d0c5e4f3990351 100644
--- a/src/core/SkMaskFilter.cpp
+++ b/src/core/SkMaskFilter.cpp
@@ -211,15 +211,16 @@ bool SkMaskFilter::filterRRect(const SkRRect& devRRect, const SkMatrix& matrix,
     // cannot be used, return false to allow our caller to recover and perform
     // the drawing another way.
     NinePatch patch;
-    patch.fMask.fImage = NULL;
+    patch.fDiscardableMemoryMask.fMask.fImage = NULL;
     if (kTrue_FilterReturn != this->filterRRectToNine(devRRect, matrix,
                                                       clip.getBounds(),
                                                       &patch)) {
-        SkASSERT(NULL == patch.fMask.fImage);
+        SkASSERT(NULL == patch.fDiscardableMemoryMask.fMask.fImage);
         return false;
     }
-    draw_nine(patch.fMask, patch.fOuterRect, patch.fCenter, true, clip, blitter);
-    SkMask::FreeImage(patch.fMask.fImage);
+    draw_nine(patch.fDiscardableMemoryMask.fMask, patch.fOuterRect, patch.fCenter, true, clip, blitter); 
+    SkScaledImageCache::Unlock(

[reed1, 2014/06/09 14:55:34]

Who set fCacheId before this Unlock call?

+        static_cast<SkScaledImageCache::ID*>(patch.fDiscardableMemoryMask.fCacheId));
     return true;
 }
 
@@ -234,21 +235,22 @@ bool SkMaskFilter::filterPath(const SkPath& devPath, const SkMatrix& matrix,
     if (rectCount > 0) {
         NinePatch patch;
 
-        patch.fMask.fImage = NULL;
+        patch.fDiscardableMemoryMask.fMask.fImage = NULL;
         switch (this->filterRectsToNine(rects, rectCount, matrix,
                                         clip.getBounds(), &patch)) {
             case kFalse_FilterReturn:
-                SkASSERT(NULL == patch.fMask.fImage);
+                SkASSERT(NULL == patch.fDiscardableMemoryMask.fMask.fImage);
                 return false;
 
             case kTrue_FilterReturn:
-                draw_nine(patch.fMask, patch.fOuterRect, patch.fCenter, 1 == rectCount, clip,
-                          blitter);
-                SkMask::FreeImage(patch.fMask.fImage);
+                draw_nine(patch.fDiscardableMemoryMask.fMask, patch.fOuterRect, patch.fCenter,
+                    1 == rectCount, clip, blitter);
+                SkScaledImageCache::Unlock(
+                    static_cast<SkScaledImageCache::ID*>(patch.fDiscardableMemoryMask.fCacheId));
                 return true;
 
             case kUnimplemented_FilterReturn:
-                SkASSERT(NULL == patch.fMask.fImage);
+                SkASSERT(NULL == patch.fDiscardableMemoryMask.fMask.fImage);
                 // fall through
                 break;
         }