Fix caret invalidation when a block is removed

third_party/WebKit/Source/core/editing/CaretDisplayItemClientTest.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "core/editing/CaretDisplayItemClient.h"
+
 #include "core/HTMLNames.h"
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutView.h"
 #include "core/page/FocusController.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/RasterInvalidationTracking.h"
 
@@ skipping 16 matching lines @@
   }
 
   FrameSelection& selection() const {
     return document().view()->frame().selection();
   }
 
   const DisplayItemClient& caretDisplayItemClient() const {
     return selection().caretDisplayItemClientForTesting();
   }
 
+  const LayoutBlock* caretLayoutBlock() const {
+    return static_cast<const CaretDisplayItemClient&>(caretDisplayItemClient())
+        .m_layoutBlock;
+  }
+
+  const LayoutBlock* previousCaretLayoutBlock() const {
+    return static_cast<const CaretDisplayItemClient&>(caretDisplayItemClient())
+        .m_previousLayoutBlock;
+  }
+
   Text* appendTextNode(const String& data) {
     Text* text = document().createTextNode(data);
     document().body()->appendChild(text);
     return text;
   }
 
   Element* appendBlock(const String& data) {
     Element* block = document().createElement("div");
     Text* text = document().createTextNode(data);
     block->appendChild(text);
@@ skipping 165 matching lines @@
   EXPECT_EQ(enclosingIntRect(caretVisualRect2), (*rasterInvalidations)[1].rect);
   EXPECT_EQ(block2, (*rasterInvalidations)[1].client);
   EXPECT_EQ(PaintInvalidationCaret, (*rasterInvalidations)[1].reason);
 
   objectInvalidations =
       document().view()->trackedObjectPaintInvalidationsAsJSON();
   ASSERT_EQ(2u, objectInvalidations->size());
   document().view()->setTracksPaintInvalidations(false);
 }
 
+TEST_F(CaretDisplayItemClientTest, UpdatePreviousLayoutBlock) {
+  document().body()->setContentEditable("true", ASSERT_NO_EXCEPTION);
+  document().page()->focusController().setActive(true);
+  document().page()->focusController().setFocused(true);
+  auto* blockElement1 = appendBlock("Block1");
+  auto* blockElement2 = appendBlock("Block2");
+  updateAllLifecyclePhases();
+  auto* block1 = toLayoutBlock(blockElement1->layoutObject());
+  auto* block2 = toLayoutBlock(blockElement2->layoutObject());
+
+  // Set caret into block2.
+  document().body()->focus();
+  selection().setSelection(SelectionInDOMTree::Builder()
+                               .collapse(Position(blockElement2, 0))
+                               .build());
+  document().view()->updateLifecycleToLayoutClean();
+  EXPECT_TRUE(block2->shouldPaintCursorCaret());
+  EXPECT_EQ(block2, caretLayoutBlock());
+  EXPECT_FALSE(block1->shouldPaintCursorCaret());
+  EXPECT_FALSE(previousCaretLayoutBlock());
+
+  // Move caret into block1. Should set previousCaretLayoutBlock to block2.
+  selection().setSelection(SelectionInDOMTree::Builder()
+                               .collapse(Position(blockElement1, 0))
+                               .build());
+  document().view()->updateLifecycleToLayoutClean();
+  EXPECT_TRUE(block1->shouldPaintCursorCaret());
+  EXPECT_EQ(block1, caretLayoutBlock());
+  EXPECT_FALSE(block2->shouldPaintCursorCaret());
+  EXPECT_EQ(block2, previousCaretLayoutBlock());
+
+  // Move caret into block2. Partial update should not change
+  // previousCaretLayoutBlock.
+  selection().setSelection(SelectionInDOMTree::Builder()
+                               .collapse(Position(blockElement2, 0))
+                               .build());
+  document().view()->updateLifecycleToLayoutClean();
+  EXPECT_TRUE(block2->shouldPaintCursorCaret());
+  EXPECT_EQ(block2, caretLayoutBlock());
+  EXPECT_FALSE(block1->shouldPaintCursorCaret());
+  EXPECT_EQ(block2, previousCaretLayoutBlock());
+
+  // Remove block2. Should clear caretLayoutBlock and previousCaretLayoutBlock.
+  blockElement2->parentNode()->removeChild(blockElement2);
+  EXPECT_FALSE(caretLayoutBlock());
+  EXPECT_FALSE(previousCaretLayoutBlock());
+
+  // Set caret into block1.
+  selection().setSelection(SelectionInDOMTree::Builder()
+                               .collapse(Position(blockElement1, 0))
+                               .build());
+  updateAllLifecyclePhases();
+  // Remove selection.
+  selection().setSelection(SelectionInDOMTree());
+  document().view()->updateLifecycleToLayoutClean();
+  EXPECT_EQ(block1, previousCaretLayoutBlock());
+}
+
 TEST_F(CaretDisplayItemClientTest, CaretHideMoveAndShow) {
   document().body()->setContentEditable("true", ASSERT_NO_EXCEPTION);
   document().page()->focusController().setActive(true);
   document().page()->focusController().setFocused(true);
 
   Text* text = appendTextNode("Hello, World!");
   document().body()->focus();
   updateAllLifecyclePhases();
   const auto* block = toLayoutBlock(document().body()->layoutObject());
 
@@ skipping 29 matching lines @@
   auto objectInvalidations =
       document().view()->trackedObjectPaintInvalidationsAsJSON();
   ASSERT_EQ(1u, objectInvalidations->size());
   String s;
   JSONObject::cast(objectInvalidations->at(0))->get("object")->asString(&s);
   EXPECT_EQ("Caret", s);
   document().view()->setTracksPaintInvalidations(false);
 }
 
 }  // namespace blink