[LayoutNG] Add initial support for collecting atomic inlines

Change NGInlineBox::PrepareLayout to collect all child nodes instead of
just non-atomic inlines and update the CollectNode method to insert the
object replacement unicode character in place of atomic inline objects.
This allows bidi resolution and text shaping to do the right thing when
operating on the entire paragraph.

Also removes the ComputedStyle pointer from NGLayoutInlineItem as it is
not needed at this point.

R=ikilpatrick@chromium.org
BUG=636993
TEST=Source/web/tests/NGInlineLayoutTest.cpp

Review-Url: https://codereview.chromium.org/2488163003
Cr-Commit-Position: refs/heads/master@{#431214}

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

@@ -16,6 +16,7 @@
 #include "core/layout/ng/ng_fragment_builder.h"
 #include "core/layout/ng/ng_length_utils.h"
 #include "core/layout/ng/ng_writing_mode.h"
+#include "wtf/text/CharacterNames.h"
 
 namespace blink {
 
@@ -29,14 +30,8 @@ void NGInlineBox::PrepareLayout() {
   // Scan list of siblings collecting all in-flow non-atomic inlines. A single
   // NGInlineBox represent a collection of adjacent non-atomic inlines.
   last_inline_ = start_inline_;
-  for (LayoutObject* curr = start_inline_; curr; curr = curr->nextSibling()) {
-    // TODO(layout-dev): We may want to include floating and OOF positioned
-    // objects.
-    if (curr->isAtomicInlineLevel() && !curr->isFloating() &&
-        !curr->isOutOfFlowPositioned())
-      break;
+  for (LayoutObject* curr = start_inline_; curr; curr = curr->nextSibling())
     last_inline_ = curr;
-  }
 
   CollectInlines(start_inline_, last_inline_);
   CollapseWhiteSpace();
@@ -49,14 +44,24 @@ void NGInlineBox::PrepareLayout() {
 // parent LayoutInline where possible, and joining all text content in a single
 // string to allow bidi resolution and shaping of the entire block.
 void NGInlineBox::CollectNode(LayoutObject* node, unsigned* offset) {
+  unsigned length = 0;
   if (node->isText()) {
     const String& text = toLayoutText(node)->text();
-    unsigned length = text.length();
+    length = text.length();
     text_content_.append(text);
+  }
+
+  // For atomic inlines add a unicode "object replacement character" to signal
+  // the presence of a non-text object to the unicode bidi algorithm.
+  else if (node->isAtomicInlineLevel()) {
+    text_content_.append(objectReplacementCharacter);
+    length = 1;
+  }
 
+  if (length) {
     unsigned start_offset = *offset;
     *offset = *offset + length;
-    items_.append(NGLayoutInlineItem(node->style(), start_offset, *offset));
+    items_.append(NGLayoutInlineItem(start_offset, *offset));
   }
 }
 

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

@@ -83,12 +83,11 @@ class CORE_EXPORT NGInlineBox final
 // element where possible.
 class NGLayoutInlineItem {
  public:
-  NGLayoutInlineItem(const ComputedStyle* style, unsigned start, unsigned end)
+  NGLayoutInlineItem(unsigned start, unsigned end)
       : start_offset_(start),
         end_offset_(end),
         direction_(LTR),
-        script_(USCRIPT_INVALID_CODE),
-        style_(style) {
+        script_(USCRIPT_INVALID_CODE) {
     DCHECK(end >= start);
   }
 
@@ -104,7 +103,6 @@ class NGLayoutInlineItem {
   UScriptCode script_;
   // FontFallbackPriority fallback_priority_;
   // bool rotate_sideways_;
-  const ComputedStyle* style_;
   RefPtr<ShapeResult> shape_result_;
 
   friend class NGInlineBox;

third_party/WebKit/Source/web/tests/NGInlineLayoutTest.cpp

@@ -14,10 +14,24 @@
 #include "web/tests/sim/SimRequest.h"
 #include "web/tests/sim/SimTest.h"
 #include "wtf/CurrentTime.h"
+#include "wtf/text/CharacterNames.h"
 
 namespace blink {
 
-class NGInlineLayoutTest : public SimTest {};
+class NGInlineLayoutTest : public SimTest {
+ public:
+  NGConstraintSpace* constraintSpaceForElement(LayoutNGBlockFlow* blockFlow) {
+    NGConstraintSpaceBuilder builder(
+        FromPlatformWritingMode(blockFlow->style()->getWritingMode()));
+    builder.SetAvailableSize(NGLogicalSize(LayoutUnit(), LayoutUnit()));
+    builder.SetPercentageResolutionSize(
+        NGLogicalSize(LayoutUnit(), LayoutUnit()));
+    NGConstraintSpace* constraintSpace = new NGConstraintSpace(
+        FromPlatformWritingMode(blockFlow->style()->getWritingMode()),
+        blockFlow->style()->direction(), builder.ToConstraintSpace());
+    return constraintSpace;
+  }
+};
 
 TEST_F(NGInlineLayoutTest, BlockWithSingleTextNode) {
   RuntimeEnabledFeatures::setLayoutNGEnabled(true);
@@ -33,15 +47,7 @@ TEST_F(NGInlineLayoutTest, BlockWithSingleTextNode) {
 
   Element* target = document().getElementById("target");
   LayoutNGBlockFlow* blockFlow = toLayoutNGBlockFlow(target->layoutObject());
-
-  NGConstraintSpaceBuilder builder(
-      FromPlatformWritingMode(blockFlow->style()->getWritingMode()));
-  builder.SetAvailableSize(NGLogicalSize(LayoutUnit(), LayoutUnit()));
-  builder.SetPercentageResolutionSize(
-      NGLogicalSize(LayoutUnit(), LayoutUnit()));
-  NGConstraintSpace* constraintSpace = new NGConstraintSpace(
-      FromPlatformWritingMode(blockFlow->style()->getWritingMode()),
-      blockFlow->style()->direction(), builder.ToConstraintSpace());
+  NGConstraintSpace* constraintSpace = constraintSpaceForElement(blockFlow);
 
   NGInlineBox* inlineBox = new NGInlineBox(blockFlow->firstChild());
   NGInlineLayoutAlgorithm* layoutAlgorithm = new NGInlineLayoutAlgorithm(
@@ -54,4 +60,32 @@ TEST_F(NGInlineLayoutTest, BlockWithSingleTextNode) {
   layoutAlgorithm->Layout(&fragment);
 }
 
+TEST_F(NGInlineLayoutTest, BlockWithTextAndAtomicInline) {
+  RuntimeEnabledFeatures::setLayoutNGEnabled(true);
+  RuntimeEnabledFeatures::setLayoutNGInlineEnabled(true);
+
+  SimRequest mainResource("https://example.com/", "text/html");
+  loadURL("https://example.com/");
+  mainResource.complete("<div id=\"target\">Hello <img>.</div>");
+
+  compositor().beginFrame();
+  ASSERT_FALSE(compositor().needsBeginFrame());
+
+  Element* target = document().getElementById("target");
+  LayoutNGBlockFlow* blockFlow = toLayoutNGBlockFlow(target->layoutObject());
+  NGConstraintSpace* constraintSpace = constraintSpaceForElement(blockFlow);
+
+  NGInlineBox* inlineBox = new NGInlineBox(blockFlow->firstChild());
+  NGInlineLayoutAlgorithm* layoutAlgorithm = new NGInlineLayoutAlgorithm(
+      blockFlow->style(), inlineBox, constraintSpace);
+
+  String expectedText("Hello ");
+  expectedText.append(objectReplacementCharacter);
+  expectedText.append(".");
+  EXPECT_EQ(expectedText, inlineBox->Text(0, 8));
+
+  NGPhysicalFragmentBase* fragment;
+  layoutAlgorithm->Layout(&fragment);
+}
+
 }  // namespace blink