Always report maybe-clipped when painting fragmented content

third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp

Index: third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp b/third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp
index d3b7553f9e31d6cbc3de2f228da01374837c4d05..6510b69d8f0e6febe02607f4417c2b1fb76147b4 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp
@@ -454,7 +454,8 @@ void PaintController::CopyCachedSubsequence(size_t begin_index,
     DCHECK(!IsCheckingUnderInvalidation());
     under_invalidation_checking_begin_ = begin_index;
     under_invalidation_message_prefix_ =
-        "(In cached subsequence of " + cached_item->Client().DebugName() + ")";
+        "(In cached subsequence starting with " +
+        cached_item->Client().DebugName() + ")";
   }
 
   Vector<PaintChunk>::const_iterator cached_chunk;
@@ -876,17 +877,6 @@ void PaintController::CheckUnderInvalidation() {
       ++skipped_probable_under_invalidation_count_;
       return;
     }
-    if (new_item.IsDrawing() &&
-        skipped_probable_under_invalidation_count_ == 1) {
-      DCHECK_GE(new_display_item_list_.size(), 2u);
-      if (new_display_item_list_[new_display_item_list_.size() - 2].GetType() ==
-          DisplayItem::kBeginCompositing) {
-        // This might be a drawing item between a pair of begin/end compositing
-        // display items that will be folded into a single drawing display item.
-        ++skipped_probable_under_invalidation_count_;

[Xianzhu, 2017/04/18 00:15:21]

Doesn't the logic apply now?

[chrishtr, 2017/04/18 21:13:13]

It doesn't, because the folding optimization in CompositingRecorder is now gone,
right?

However, that CL was reverted again yesterday, so re-adding this code for now.

-        return;
-      }
-    }
   }
 
   if (skipped_probable_under_invalidation_count_ || !old_and_new_equal) {