[SPv2] Fix layout test crashes about raster invalidation

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 c5ee0d2dcc69c2d3d5ab7f4d6cfc8b4a27faec58..a33275a9caf094a446007ed0d8ecb3e7b1ac1dae 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp
@@ -21,12 +21,13 @@ static constexpr int kMaxNumberOfSlowPathsBeforeVeto = 5;
 namespace blink {
 
 void PaintController::SetTracksRasterInvalidations(bool value) {
-  if (value) {
-    paint_chunks_raster_invalidation_tracking_map_ =
+  if (value ||
+      RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled()) {
+    raster_invalidation_tracking_map_ =
         WTF::WrapUnique(new RasterInvalidationTrackingMap<const PaintChunk>);
-  } else {
-    paint_chunks_raster_invalidation_tracking_map_ = nullptr;
+    return;
   }
+  raster_invalidation_tracking_map_ = nullptr;
 }
 
 const PaintArtifact& PaintController::GetPaintArtifact() const {
@@ -597,9 +598,15 @@ void PaintController::CommitNewDisplayItems(
 
   // The new list will not be appended to again so we can release unused memory.
   new_display_item_list_.ShrinkToFit();
+
+  if (raster_invalidation_tracking_map_) {
+    for (const auto& chunk : current_paint_artifact_.PaintChunks())
+      raster_invalidation_tracking_map_->Remove(&chunk);
+  }
   current_paint_artifact_ = PaintArtifact(
       std::move(new_display_item_list_), new_paint_chunks_.ReleasePaintChunks(),
       num_slow_paths <= kMaxNumberOfSlowPathsBeforeVeto);
+
   ResetCurrentListIndices();
   out_of_order_item_indices_.clear();
   out_of_order_chunk_indices_.clear();
@@ -676,7 +683,7 @@ void PaintController::GenerateChunkRasterInvalidationRects(
 
   static FloatRect infinite_float_rect(LayoutRect::InfiniteIntRect());
   if (!new_chunk.id) {
-    AddRasterInvalidationInfo(nullptr, new_chunk, infinite_float_rect);
+    AddRasterInvalidation(nullptr, new_chunk, infinite_float_rect);
     return;
   }
 
@@ -718,14 +725,14 @@ void PaintController::GenerateChunkRasterInvalidationRects(
   }
 
   // We reach here because the chunk is new.
-  AddRasterInvalidationInfo(nullptr, new_chunk, infinite_float_rect);
+  AddRasterInvalidation(nullptr, new_chunk, infinite_float_rect);
 }
 
-void PaintController::AddRasterInvalidationInfo(const DisplayItemClient* client,
-                                                PaintChunk& chunk,
-                                                const FloatRect& rect) {
+void PaintController::AddRasterInvalidation(const DisplayItemClient* client,
+                                            PaintChunk& chunk,
+                                            const FloatRect& rect) {
   chunk.raster_invalidation_rects.push_back(rect);
-  if (!paint_chunks_raster_invalidation_tracking_map_)
+  if (!raster_invalidation_tracking_map_)
     return;
   RasterInvalidationInfo info;
   info.rect = EnclosingIntRect(rect);
@@ -734,9 +741,7 @@ void PaintController::AddRasterInvalidationInfo(const DisplayItemClient* client,
     info.client_debug_name = client->DebugName();
     info.reason = client->GetPaintInvalidationReason();
   }
-  RasterInvalidationTracking& tracking =
-      paint_chunks_raster_invalidation_tracking_map_->Add(&chunk);
-  tracking.tracked_raster_invalidations.push_back(info);
+  raster_invalidation_tracking_map_->AddInvalidation(&chunk, info);
 }
 
 void PaintController::GenerateChunkRasterInvalidationRectsComparingOldChunk(
@@ -747,6 +752,19 @@ void PaintController::GenerateChunkRasterInvalidationRectsComparingOldChunk(
   // TODO(wangxianzhu): Handle PaintInvalidationIncremental.
   // TODO(wangxianzhu): Optimize paint offset change.
 
+  // We may track raster invalidations across multiple paints. The new chunk
+  // should contain all previously tracked invalidations.
+  if (raster_invalidation_tracking_map_) {
+    // Add() must be before Find() otherwise Add() might invalidate the pointer
+    // returned from Find().
+    auto& new_tracking = raster_invalidation_tracking_map_->Add(&new_chunk);
+    if (auto* old_tracking =
+            raster_invalidation_tracking_map_->Find(&old_chunk)) {
+      new_tracking.tracked_invalidations.AppendVector(
+          old_tracking->tracked_invalidations);
+    }
+  }
+
   HashSet<const DisplayItemClient*> invalidated_clients_in_old_chunk;
   size_t highest_moved_to_index = 0;
   for (size_t old_index = old_chunk.begin_index;
@@ -767,9 +785,8 @@ void PaintController::GenerateChunkRasterInvalidationRectsComparingOldChunk(
           // And invalidate in the new chunk into which the item was moved.
           PaintChunk& moved_to_chunk =
               new_paint_chunks_.FindChunkByDisplayItemIndex(moved_to_index);
-          AddRasterInvalidationInfo(
-              client_to_invalidate, moved_to_chunk,
-              FloatRect(client_to_invalidate->VisualRect()));
+          AddRasterInvalidation(client_to_invalidate, moved_to_chunk,
+                                FloatRect(client_to_invalidate->VisualRect()));
         } else if (moved_to_index < highest_moved_to_index) {
           // The item has been moved behind other cached items, so need to
           // invalidate the area that is probably exposed by the item moved
@@ -787,7 +804,7 @@ void PaintController::GenerateChunkRasterInvalidationRectsComparingOldChunk(
     if (client_to_invalidate &&
         invalidated_clients_in_old_chunk.insert(client_to_invalidate)
             .is_new_entry) {
-      AddRasterInvalidationInfo(
+      AddRasterInvalidation(
           is_potentially_invalid_client ? nullptr : client_to_invalidate,
           new_chunk,
           FloatRect(current_paint_artifact_.GetDisplayItemList().VisualRect(
@@ -802,8 +819,8 @@ void PaintController::GenerateChunkRasterInvalidationRectsComparingOldChunk(
     if (new_item.DrawsContent() && !ClientCacheIsValid(new_item.Client()) &&
         invalidated_clients_in_new_chunk.insert(&new_item.Client())
             .is_new_entry) {
-      AddRasterInvalidationInfo(&new_item.Client(), new_chunk,
-                                FloatRect(new_item.Client().VisualRect()));
+      AddRasterInvalidation(&new_item.Client(), new_chunk,
+                            FloatRect(new_item.Client().VisualRect()));
     }
   }
 }