[LayoutNG] Introduce block child iterator.

third_party/WebKit/Source/core/layout/ng/ng_block_child_iterator_test.cc

+// 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/layout/ng/ng_block_child_iterator.h"
+
+#include "core/layout/LayoutTestHelper.h"
+#include "core/layout/ng/ng_block_break_token.h"
+#include "core/layout/ng/ng_block_node.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+namespace {
+
+#define CHILD_TOKEN_PAIR(child, token)                   \
+  std::make_pair(static_cast<NGLayoutInputNode*>(child), \
+                 static_cast<NGBreakToken*>(token))
+
+class NGBlockChildIteratorTest : public RenderingTest {};
+
+TEST_F(NGBlockChildIteratorTest, testNullFirstChild) {
+  NGBlockChildIterator iterator(nullptr, nullptr);
+  EXPECT_EQ(CHILD_TOKEN_PAIR(nullptr, nullptr), iterator.NextChild());
+}
+
+TEST_F(NGBlockChildIteratorTest, testNoBreakToken) {
+  setBodyInnerHTML(R"HTML(

[mstensho (USE GERRIT), 2017/02/22 13:11:31]

I see that setBodyInnerHTML() is used in existing ng tests already, but do you
have any thoughts on the fact that setBodyInnerHTML() will actually lay out with
the current layout engine first?

[ikilpatrick, 2017/02/22 18:47:19]

We may want our own test runner which just updates the document to
updateStyleAndLayoutTree... i've been mainly using this just so that we can get
LayoutObjects instead of building up style manually.

Thoughts?

[mstensho (USE GERRIT), 2017/02/22 20:09:23]

Yeah, something like that. Sorry for bringing it up in a review, though; that
probably wasn't the right place. :)

Just having the LayoutObject tree and computed style (without laying it out)
would be a good first step. Building up style and input nodes manually is
something few people would enjoy writing (or reading) all day long, so
setBodyInnerHTML() is way superior to that. :)

[ikilpatrick, 2017/02/22 22:25:21]

Np :), I might go through and normalize all our tests to look the same, at the
moment its a little bit all over the place :/

+      <div id='child1'></div>
+      <div id='child2'></div>
+      <div id='child3'></div>
+    )HTML");
+  NGLayoutInputNode* node1 = new NGBlockNode(
+      toLayoutBlockFlow(document().getElementById("child1")->layoutObject()));

[mstensho (USE GERRIT), 2017/02/22 13:11:31]

You can use getLayoutObjectByElementId("id") instead of
document().getElementById("id")->layoutObject().

[ikilpatrick, 2017/02/22 18:47:20]

Done.

+  NGLayoutInputNode* node2 = node1->NextSibling();
+  NGLayoutInputNode* node3 = node2->NextSibling();
+
+  // The iterator should loop through three children.
+  NGBlockChildIterator iterator(node1, nullptr);
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node1, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node2, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node3, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(nullptr, nullptr), iterator.NextChild());
+}
+
+TEST_F(NGBlockChildIteratorTest, testBreakTokenWithFinishedChild) {
+  setBodyInnerHTML(R"HTML(
+      <div id='container'>
+        <div id='child1'></div>
+        <div id='child2'></div>
+        <div id='child3'></div>
+      </div>
+    )HTML");
+  NGBlockNode* container = new NGBlockNode(toLayoutBlockFlow(
+      document().getElementById("container")->layoutObject()));
+  NGLayoutInputNode* node1 = container->FirstChild();
+  NGLayoutInputNode* node2 = node1->NextSibling();
+  NGLayoutInputNode* node3 = node2->NextSibling();
+
+  HeapVector<Member<NGBreakToken>> child_break_tokens;
+  child_break_tokens.push_back(new NGBlockBreakToken(toNGBlockNode(node1)));
+  NGBlockBreakToken* parent_token =
+      new NGBlockBreakToken(container, LayoutUnit(50), child_break_tokens);
+
+  // The iterator should loop through two children.
+  NGBlockChildIterator iterator(node1, parent_token);
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node2, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node3, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(nullptr, nullptr), iterator.NextChild());
+
+  HeapVector<Member<NGBreakToken>> child_break_tokens2;

[mstensho (USE GERRIT), 2017/02/22 13:11:31]

Unused. Did you mean to use it below? Otherwise, just remove it. Re-using
child_break_tokens, like you currently do, should work fine, since
NGBlockBreakToken() eats the children.

[ikilpatrick, 2017/02/22 18:47:20]

Removed, and from other test.

+  child_break_tokens.push_back(new NGBlockBreakToken(toNGBlockNode(node2)));
+  parent_token =
+      new NGBlockBreakToken(container, LayoutUnit(50), child_break_tokens);
+
+  // The iterator should loop through two children.
+  NGBlockChildIterator iterator2(node1, parent_token);
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node1, nullptr), iterator2.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node3, nullptr), iterator2.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(nullptr, nullptr), iterator2.NextChild());
+}
+
+TEST_F(NGBlockChildIteratorTest, testBreakTokenWithUnFinishedChild) {
+  setBodyInnerHTML(R"HTML(
+      <div id='container'>
+        <div id='child1'></div>
+        <div id='child2'></div>
+        <div id='child3'></div>
+      </div>
+    )HTML");
+  NGBlockNode* container = new NGBlockNode(toLayoutBlockFlow(
+      document().getElementById("container")->layoutObject()));
+  NGLayoutInputNode* node1 = container->FirstChild();
+  NGLayoutInputNode* node2 = node1->NextSibling();
+  NGLayoutInputNode* node3 = node2->NextSibling();
+
+  HeapVector<Member<NGBreakToken>> child_break_tokens;
+  NGBreakToken* child_token = new NGBlockBreakToken(
+      toNGBlockNode(node1), LayoutUnit(), child_break_tokens);
+  child_break_tokens.push_back(child_token);
+  NGBlockBreakToken* parent_token =
+      new NGBlockBreakToken(container, LayoutUnit(50), child_break_tokens);
+
+  // The iterator should loop through three children, one with a break token.
+  NGBlockChildIterator iterator(node1, parent_token);
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node1, child_token), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node2, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node3, nullptr), iterator.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(nullptr, nullptr), iterator.NextChild());
+
+  HeapVector<Member<NGBreakToken>> child_break_tokens2;
+  child_token = new NGBlockBreakToken(toNGBlockNode(node2), LayoutUnit(),
+                                      child_break_tokens2);
+  child_break_tokens2.push_back(child_token);
+  parent_token =
+      new NGBlockBreakToken(container, LayoutUnit(50), child_break_tokens2);
+
+  // The iterator should loop through three children, one with a break token.
+  NGBlockChildIterator iterator2(node1, parent_token);
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node1, nullptr), iterator2.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node2, child_token), iterator2.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(node3, nullptr), iterator2.NextChild());
+  EXPECT_EQ(CHILD_TOKEN_PAIR(nullptr, nullptr), iterator2.NextChild());
+}
+
+}  // namespace
+}  // namespace blink