Add a new VisibleUnitsLine unit test

This patch records some InSameLine() call results as a preparation for
implementing NG InSameLine().

Bug: 830956
Change-Id: Ia1a2a9b80363fa20be570638f057ccc8895d7a30
Reviewed-on: https://chromium-review.googlesource.com/1008173Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549997}

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

@@ -599,4 +599,28 @@ TEST_F(VisibleUnitsLineTest,
                 two->lastChild(), visible_position, kContentIsEditable));
 }
 
+TEST_F(VisibleUnitsLineTest, InSameLineSkippingEmptyEditableDiv) {
+  // This test records the InSameLine() results in
+  // editing/selection/skip-over-contenteditable.html
+  SetBodyContent(
+      "<p id=foo>foo</p>"
+      "<div contenteditable></div>"
+      "<p id=bar>bar</p>");
+  const Node* const foo = GetElementById("foo")->firstChild();
+  const Node* const bar = GetElementById("bar")->firstChild();
+
+  EXPECT_TRUE(InSameLine(
+      PositionWithAffinity(Position(foo, 3), TextAffinity::kDownstream),
+      PositionWithAffinity(Position(foo, 3), TextAffinity::kUpstream)));
+  EXPECT_FALSE(InSameLine(
+      PositionWithAffinity(Position(bar, 0), TextAffinity::kDownstream),
+      PositionWithAffinity(Position(foo, 3), TextAffinity::kDownstream)));
+  EXPECT_TRUE(InSameLine(
+      PositionWithAffinity(Position(bar, 3), TextAffinity::kDownstream),
+      PositionWithAffinity(Position(bar, 3), TextAffinity::kUpstream)));
+  EXPECT_FALSE(InSameLine(
+      PositionWithAffinity(Position(foo, 0), TextAffinity::kDownstream),
+      PositionWithAffinity(Position(bar, 0), TextAffinity::kDownstream)));
+}
+
 }  // namespace blink