Find cached display items directly during painting

third_party/WebKit/Source/core/paint/README.md

Index: third_party/WebKit/Source/core/paint/README.md
diff --git a/third_party/WebKit/Source/core/paint/README.md b/third_party/WebKit/Source/core/paint/README.md
index 1972dea766b69edd900fadf1de7dcc15f113d270..c3912685d6caabedbda5b49e3dbb73caf401a385 100644
--- a/third_party/WebKit/Source/core/paint/README.md
+++ b/third_party/WebKit/Source/core/paint/README.md
@@ -215,9 +215,8 @@ we'll skip the painting and reuse the display items from cache.
 
 ### Display item caching
 
-We'll create a `CachedDisplayItem` when a painter would create a `DrawingDisplayItem` exactly
-the same as the display item created in the previous painting. After painting, `PaintController`
-will replace `CachedDisplayItem` with the corresponding display item from the cache.
+When a painter would create a `DrawingDisplayItem` exactly the same as the display item
+created in the previous painting, we'll reuse the previous one instead of repainting it.
 
 ### Subsequence caching
 
@@ -225,10 +224,8 @@ When possible, we enclose the display items that `PaintLayerPainter::paintConten
 (including display items generated by sublayers) in a pair of `BeginSubsequence/EndSubsequence`
 display items.
 
-In a subsequence paint, if the layer would generate exactly the same display items, we'll simply
-output a `CachedSubsequence` display item in place of the display items, and skip all paintings
-of the layer and its descendants in painting order. After painting, `PaintController` will
-replace `CacheSubsequence` with cached display items created in previous paintings.
+In a subsequence paint, if the layer would generate exactly the same display items, we'll get
+the whole subsequence from the cache instead of repainting them.
 
 There are many conditions affecting
 *   whether we need to generate subsequence for a PaintLayer;