[LayoutNG] Add NGLineBoxFragment

This patch adds NGLineBoxFragment, along with:
- NGPhysicalLineBoxFragment
- NGLineBoxFragmentBuilder
- NGTextFragmentBuilder for consistency

Part of code in NGLineBuilder was extracted to new classes, in
preparation of renaming it to NGLineLayoutAlgorithm.

NGFragment::Overflow was moved to NGBoxFragment, since neither text nor
linebox has layout overflow. All types of fragments have ink overflow,
but this is not included in this CL.

Some of NGFragmentBuilders could be shared as super classes. This is not
in this CL but to be discussed further.

This patch moves one step towards computing baseline position from
NGFragment, but its implementation is not included in this CL.

BUG=636993

Review-Url: https://codereview.chromium.org/2764753007
Cr-Commit-Position: refs/heads/master@{#459446}

third_party/WebKit/Source/core/layout/BUILD.gn

@@ -361,8 +361,14 @@ blink_core_sources("layout") {
     "ng/ng_layout_result.h",
     "ng/ng_length_utils.cc",
     "ng/ng_length_utils.h",
+    "ng/ng_line_box_fragment.cc",
+    "ng/ng_line_box_fragment.h",
+    "ng/ng_line_box_fragment_builder.cc",
+    "ng/ng_line_box_fragment_builder.h",
     "ng/ng_line_builder.cc",
     "ng/ng_line_builder.h",
+    "ng/ng_line_height_metrics.cc",
+    "ng/ng_line_height_metrics.h",
     "ng/ng_macros.h",
     "ng/ng_min_max_content_size.cc",
     "ng/ng_min_max_content_size.h",
@@ -372,13 +378,17 @@ blink_core_sources("layout") {
     "ng/ng_physical_box_fragment.h",
     "ng/ng_physical_fragment.cc",
     "ng/ng_physical_fragment.h",
+    "ng/ng_physical_line_box_fragment.cc",
+    "ng/ng_physical_line_box_fragment.h",
     "ng/ng_physical_text_fragment.h",
     "ng/ng_relative_utils.cc",
     "ng/ng_relative_utils.h",
     "ng/ng_space_utils.cc",
     "ng/ng_space_utils.h",
     "ng/ng_text_fragment.cc",
     "ng/ng_text_fragment.h",
+    "ng/ng_text_fragment_builder.cc",
+    "ng/ng_text_fragment_builder.h",
     "ng/ng_text_layout_algorithm.cc",
     "ng/ng_text_layout_algorithm.h",
     "ng/ng_writing_mode.cc",

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

@@ -9,6 +9,18 @@
 
 namespace blink {
 
+LayoutUnit NGBoxFragment::InlineOverflow() const {
+  return writing_mode_ == kHorizontalTopBottom
+             ? toNGPhysicalBoxFragment(physical_fragment_)->WidthOverflow()
+             : toNGPhysicalBoxFragment(physical_fragment_)->HeightOverflow();
+}
+
+LayoutUnit NGBoxFragment::BlockOverflow() const {
+  return writing_mode_ == kHorizontalTopBottom
+             ? toNGPhysicalBoxFragment(physical_fragment_)->HeightOverflow()
+             : toNGPhysicalBoxFragment(physical_fragment_)->WidthOverflow();
+}
+
 const WTF::Optional<NGLogicalOffset>& NGBoxFragment::BfcOffset() const {
   WRITING_MODE_IGNORED(
       "Accessing BFC offset is allowed here because writing"

third_party/WebKit/Source/core/layout/ng/ng_box_fragment.h

@@ -18,6 +18,10 @@ class CORE_EXPORT NGBoxFragment final : public NGFragment {
                 const NGPhysicalBoxFragment* physical_fragment)
       : NGFragment(writing_mode, physical_fragment) {}
 
+  // Returns the total size, including the contents outside of the border-box.
+  LayoutUnit InlineOverflow() const;
+  LayoutUnit BlockOverflow() const;
+
   const WTF::Optional<NGLogicalOffset>& BfcOffset() const;
 
   const NGMarginStrut& EndMarginStrut() const;

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

@@ -16,18 +16,6 @@ LayoutUnit NGFragment::BlockSize() const {
                                                : physical_fragment_->Width();
 }
 
-LayoutUnit NGFragment::InlineOverflow() const {
-  return writing_mode_ == kHorizontalTopBottom
-             ? physical_fragment_->WidthOverflow()
-             : physical_fragment_->HeightOverflow();
-}
-
-LayoutUnit NGFragment::BlockOverflow() const {
-  return writing_mode_ == kHorizontalTopBottom
-             ? physical_fragment_->HeightOverflow()
-             : physical_fragment_->WidthOverflow();
-}
-
 LayoutUnit NGFragment::InlineOffset() const {
   return writing_mode_ == kHorizontalTopBottom
              ? physical_fragment_->LeftOffset()

third_party/WebKit/Source/core/layout/ng/ng_fragment.h

@@ -25,10 +25,6 @@ class CORE_EXPORT NGFragment {
   LayoutUnit InlineSize() const;
   LayoutUnit BlockSize() const;
 
-  // Returns the total size, including the contents outside of the border-box.
-  LayoutUnit InlineOverflow() const;
-  LayoutUnit BlockOverflow() const;
-
   // Returns the offset relative to the parent fragment's content-box.
   LayoutUnit InlineOffset() const;
   LayoutUnit BlockOffset() const;

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

@@ -161,7 +161,6 @@ NGFragmentBuilder& NGFragmentBuilder::AddOutOfFlowDescendant(
 }
 
 RefPtr<NGLayoutResult> NGFragmentBuilder::ToBoxFragment() {
-  // TODO(layout-ng): Support text fragments
   DCHECK_EQ(type_, NGPhysicalFragment::kFragmentBox);
   DCHECK_EQ(offsets_.size(), children_.size());
 
@@ -198,18 +197,4 @@ RefPtr<NGLayoutResult> NGFragmentBuilder::ToBoxFragment() {
                          out_of_flow_positions_, unpositioned_floats_));
 }
 
-RefPtr<NGPhysicalTextFragment> NGFragmentBuilder::ToTextFragment(
-    unsigned index,
-    unsigned start_offset,
-    unsigned end_offset) {
-  DCHECK_EQ(type_, NGPhysicalFragment::kFragmentText);
-  DCHECK(children_.isEmpty());
-  DCHECK(offsets_.isEmpty());
-
-  return adoptRef(new NGPhysicalTextFragment(
-      node_->GetLayoutObject(), toNGInlineNode(node_), index, start_offset,
-      end_offset, size_.ConvertToPhysical(writing_mode_),
-      overflow_.ConvertToPhysical(writing_mode_)));
-}
-
 }  // namespace blink

third_party/WebKit/Source/core/layout/ng/ng_fragment_builder.h

@@ -99,9 +99,6 @@ class CORE_EXPORT NGFragmentBuilder final {
 
   // Creates the fragment. Can only be called once.
   RefPtr<NGLayoutResult> ToBoxFragment();
-  RefPtr<NGPhysicalTextFragment> ToTextFragment(unsigned index,
-                                                unsigned start_offset,
-                                                unsigned end_offset);
 
   Vector<RefPtr<NGPhysicalFragment>>& MutableChildren() { return children_; }
 

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

@@ -10,6 +10,7 @@
 #include "core/layout/ng/ng_fragment_builder.h"
 #include "core/layout/ng/ng_line_builder.h"
 #include "core/layout/ng/ng_physical_box_fragment.h"
+#include "core/layout/ng/ng_physical_line_box_fragment.h"
 #include "core/layout/ng/ng_physical_text_fragment.h"
 #include "core/layout/ng/ng_text_fragment.h"
 #include "core/layout/ng/ng_text_layout_algorithm.h"
@@ -98,9 +99,12 @@ class NGInlineNodeTest : public RenderingTest {
     algorithm.LayoutInline(&line_builder);
 
     RefPtr<NGLayoutResult> result = line_builder.CreateFragments();
-    for (const auto& child :
-         toNGPhysicalBoxFragment(result->PhysicalFragment().get())
-             ->Children()) {
+    const NGPhysicalBoxFragment* container =
+        toNGPhysicalBoxFragment(result->PhysicalFragment().get());
+    EXPECT_EQ(container->Children().size(), 1u);
+    const NGPhysicalLineBoxFragment* line =
+        toNGPhysicalLineBoxFragment(container->Children()[0].get());
+    for (const auto& child : line->Children()) {
       fragments_out->push_back(toNGPhysicalTextFragment(child.get()));
     }
   }

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

@@ -0,0 +1,7 @@
+// 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_line_box_fragment.h"
+
+namespace blink {}  // namespace blink

third_party/WebKit/Source/core/layout/ng/ng_line_box_fragment.h

@@ -0,0 +1,30 @@
+// 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.
+
+#ifndef NGLineBoxFragment_h
+#define NGLineBoxFragment_h
+
+#include "core/CoreExport.h"
+#include "core/layout/ng/ng_fragment.h"
+#include "core/layout/ng/ng_physical_line_box_fragment.h"
+#include "core/layout/ng/ng_writing_mode.h"
+
+namespace blink {
+
+class CORE_EXPORT NGLineBoxFragment final : public NGFragment {
+ public:
+  NGLineBoxFragment(NGWritingMode writing_mode,
+                    const NGPhysicalLineBoxFragment* physical_fragment)
+      : NGFragment(writing_mode, physical_fragment) {}
+};
+
+DEFINE_TYPE_CASTS(NGLineBoxFragment,
+                  NGFragment,
+                  fragment,
+                  fragment->Type() == NGPhysicalFragment::kFragmentLineBox,
+                  fragment.Type() == NGPhysicalFragment::kFragmentLineBox);
+
+}  // namespace blink
+
+#endif  // NGLineBoxFragment_h

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

@@ -0,0 +1,70 @@
+// 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_line_box_fragment_builder.h"
+
+#include "core/layout/ng/geometry/ng_logical_size.h"
+#include "core/layout/ng/ng_fragment.h"
+#include "core/layout/ng/ng_inline_node.h"
+#include "core/layout/ng/ng_physical_line_box_fragment.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+NGLineBoxFragmentBuilder::NGLineBoxFragmentBuilder(NGInlineNode* node)
+    : direction_(TextDirection::kLtr), node_(node) {}
+
+NGLineBoxFragmentBuilder& NGLineBoxFragmentBuilder::SetDirection(
+    TextDirection direction) {
+  direction_ = direction;
+  return *this;
+}
+
+NGLineBoxFragmentBuilder& NGLineBoxFragmentBuilder::SetInlineSize(
+    LayoutUnit size) {
+  inline_size_ = size;
+  return *this;
+}
+
+NGLineBoxFragmentBuilder& NGLineBoxFragmentBuilder::AddChild(
+    RefPtr<NGPhysicalFragment> child,
+    const NGLogicalOffset& child_offset) {
+  children_.push_back(std::move(child));
+  offsets_.push_back(child_offset);
+
+  return *this;
+}
+
+void NGLineBoxFragmentBuilder::MoveChildrenInBlockDirection(LayoutUnit delta) {
+  for (auto& offset : offsets_)
+    offset.block_offset += delta;
+}
+
+void NGLineBoxFragmentBuilder::UniteMetrics(
+    const NGLineHeightMetrics& metrics) {
+  metrics_.Unite(metrics);
+}
+
+RefPtr<NGPhysicalLineBoxFragment>
+NGLineBoxFragmentBuilder::ToLineBoxFragment() {
+  DCHECK_EQ(offsets_.size(), children_.size());
+
+  NGWritingMode writing_mode(
+      FromPlatformWritingMode(node_->BlockStyle()->getWritingMode()));
+  NGPhysicalSize physical_size =
+      NGLogicalSize(inline_size_, Metrics().LineHeight())
+          .ConvertToPhysical(writing_mode);
+
+  for (size_t i = 0; i < children_.size(); ++i) {
+    NGPhysicalFragment* child = children_[i].get();
+    child->SetOffset(offsets_[i].ConvertToPhysical(
+        writing_mode, direction_, physical_size, child->Size()));
+  }
+
+  // TODO(kojii): Implement BreakToken.
+  return adoptRef(new NGPhysicalLineBoxFragment(physical_size, children_,
+                                                metrics_, nullptr));
+}
+
+}  // namespace blink

third_party/WebKit/Source/core/layout/ng/ng_line_box_fragment_builder.h

@@ -0,0 +1,57 @@
+// 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.
+
+#ifndef NGLineBoxFragmentBuilder_h
+#define NGLineBoxFragmentBuilder_h
+
+#include "core/layout/ng/geometry/ng_logical_offset.h"
+#include "core/layout/ng/ng_line_height_metrics.h"
+#include "wtf/Allocator.h"
+
+namespace blink {
+
+class NGInlineNode;
+class NGPhysicalFragment;
+class NGPhysicalLineBoxFragment;
+
+class CORE_EXPORT NGLineBoxFragmentBuilder final {
+  STACK_ALLOCATED();
+
+ public:
+  NGLineBoxFragmentBuilder(NGInlineNode*);
+
+  NGLineBoxFragmentBuilder& SetDirection(TextDirection);
+
+  NGLineBoxFragmentBuilder& SetInlineSize(LayoutUnit);
+
+  NGLineBoxFragmentBuilder& AddChild(RefPtr<NGPhysicalFragment>,
+                                     const NGLogicalOffset&);
+  void MoveChildrenInBlockDirection(LayoutUnit);
+
+  const Vector<RefPtr<NGPhysicalFragment>>& Children() const {
+    return children_;
+  }
+
+  void UniteMetrics(const NGLineHeightMetrics&);
+  const NGLineHeightMetrics& Metrics() const { return metrics_; }
+
+  // Creates the fragment. Can only be called once.
+  RefPtr<NGPhysicalLineBoxFragment> ToLineBoxFragment();
+
+ private:
+  TextDirection direction_;
+
+  Persistent<NGInlineNode> node_;
+
+  LayoutUnit inline_size_;
+
+  Vector<RefPtr<NGPhysicalFragment>> children_;
+  Vector<NGLogicalOffset> offsets_;
+
+  NGLineHeightMetrics metrics_;
+};
+
+}  // namespace blink
+
+#endif  // NGLineBoxFragmentBuilder