Reland "Fix caret rendering when at the end of a block after an ineditable inline"

This reverts commit 6d77a353.

Reason for reland: Max recursion depth is reduced to avoid stack
overflow.

Original change's description:
> Revert "Fix caret rendering when at the end of a block after an ineditable inline"
> 
> This reverts commit e9aa20fd.
> 
> Reason for revert: this change breaks tests on win dbg bot
> 
> This is the first failure
> https://ci.chromium.org/p/chromium/builders/ci/Win10%20Tests%20x64%20%28dbg%29/6437
> 
> Test InsertListCommandTest.CleanupNodeSameAsDestinationNode is definitely fails because of this patch (I've verified it locally on Windows).
> The problem with this test that it's very deep recursion in function between functions
> AdjustBlockFlowPositionToInline
> ComputeInlineAdjustedPositionAlgorithm
> 
> and as a result stack overflow.
> 
> 
> Original change's description:
> > Fix caret rendering when at the end of a block after an ineditable inline
> >
> > AdjustBlockFlowPositionToInline() has an early-reject branch that avoids
> > infinite recursion, introduced in crrev.com/664b6437.
> >
> > However, the early reject condition is too aggressive that, it also
> > rejects some positions that don't enter an infinite recursion, like
> > the one used in the new unit test added in this CL.
> >
> > As now AdjustBlockFlowPositionToInline() has a hard limit on recursion
> > depth, this CL safely removes the over-aggressive reject condition, so
> > that caret can be correctly rendered for more positions.
> >
> > Note: Unit test InlineBoxPositionTest.ComputeInlineBoxPositionMixedEditable
> > uses another position that doesn't enter the infinite loop but is falsely
> > rejected by the condition. This patch allows caret rendering also for that
> > position, and therefore changes its test expectation.
> >
> > Bug: 936988
> > Change-Id: Idef91ffaa412e67cddd5fcf0dd61f54055de7189
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1497466
> > Auto-Submit: Xiaocheng Hu <xiaochengh@chromium.org>
> > Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
> > Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#637311}
> 
> TBR=yosin@chromium.org,yoichio@chromium.org,xiaochengh@chromium.org
> 
> Change-Id: I6fcff118f27d633e627d5942671b04554fef283b
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 936988
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1503579
> Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
> Commit-Queue: Vadym Doroshenko <dvadym@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#637676}

TBR=yosin@chromium.org,yoichio@chromium.org,dvadym@chromium.org,xiaochengh@chromium.org

Change-Id: Ic959d3d57558995a315269bb938b75307efb6ea8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 936988
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504226
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637832}

third_party/blink/renderer/core/editing/inline_box_position.cc

@@ -45,7 +45,7 @@ namespace blink {
 
 namespace {
 
-const int kBlockFlowAdjustmentMaxRecursionDepth = 1024;
+const int kBlockFlowAdjustmentMaxRecursionDepth = 256;
 
 bool IsNonTextLeafChild(LayoutObject* object) {
   if (object->SlowFirstChild())
@@ -217,8 +217,7 @@ PositionWithAffinityTemplate<Strategy> AdjustBlockFlowPositionToInline(
   }
   const PositionTemplate<Strategy>& upstream_equivalent =
       UpstreamIgnoringEditingBoundaries(position);
-  if (upstream_equivalent == position ||
-      DownstreamIgnoringEditingBoundaries(upstream_equivalent) == position)
+  if (upstream_equivalent == position)
     return PositionWithAffinityTemplate<Strategy>();
 
   return ComputeInlineAdjustedPositionAlgorithm(

third_party/blink/renderer/core/editing/inline_box_position_test.cc

@@ -49,12 +49,15 @@ TEST_F(InlineBoxPositionTest, ComputeInlineBoxPositionMixedEditable) {
   SetBodyContent(
       "<div contenteditable id=sample>abc<input contenteditable=false></div>");
   Element* const sample = GetDocument().getElementById("sample");
+  Element* const input = GetDocument().QuerySelector("input");
+  const InlineBox* const input_wrapper_box =
+      ToLayoutBox(input->GetLayoutObject())->InlineBoxWrapper();
 
   const InlineBoxPosition& actual = ComputeInlineBoxPosition(
       PositionWithAffinity(Position::LastPositionInNode(*sample)));
   // Should not be in infinite-loop
-  EXPECT_EQ(nullptr, actual.inline_box);
-  EXPECT_EQ(0, actual.offset_in_box);
+  EXPECT_EQ(input_wrapper_box, actual.inline_box);
+  EXPECT_EQ(1, actual.offset_in_box);
 }
 
 // http://crbug.com/841363

third_party/blink/renderer/core/editing/local_caret_rect_test.cc

@@ -972,4 +972,21 @@ TEST_P(ParameterizedLocalCaretRectTest, AfterCollapsedWhiteSpaceInRTLText) {
                 PositionWithAffinity(position, TextAffinity::kDownstream)));
 }
 
+// https://crbug.com/936988
+TEST_P(ParameterizedLocalCaretRectTest, AfterIneditableInline) {
+  // For LayoutNG, we also enable EditingNG to test NG caret rendering.
+  ScopedEditingNGForTest editing_ng(LayoutNGEnabled());
+
+  LoadAhem();
+  InsertStyleElement("div { font: 10px/10px Ahem }");
+  SetBodyContent(
+      "<div contenteditable><span contenteditable=\"false\">foo</span></div>");
+  const Element* div = GetDocument().QuerySelector("div");
+  const Node* text = div->firstChild()->firstChild();
+
+  const Position position = Position::LastPositionInNode(*div);
+  EXPECT_EQ(LocalCaretRect(text->GetLayoutObject(), LayoutRect(30, 0, 1, 10)),
+            LocalCaretRectOfPosition(PositionWithAffinity(position)));
+}
+
 }  // namespace blink