[LayoutNG] Fix ::first-line edge case and Inspector getPlatformFonts

This patch fixes:
1. ::first-line style is not applied when there are other
   anonymous inline boxes.
2. Inspector getPlatformFonts protocol collects fonts from
   two levels deep. Changed the logic not to include
   anonymous boxes to the depth limit.

Also the incorrect expectation was fixed; legacy counts
glyphs in ::first-letter twice.

Bug: 636993, 714962
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Ia028710b728e8e9172b540a46b42d804c9f57699
Reviewed-on: https://chromium-review.googlesource.com/1245078Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594395}

third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-features=LayoutNG

@@ -426,7 +426,6 @@ crbug.com/591099 idle-callback/test-runner-run-idle-tasks.html [ Crash Pass Time
 crbug.com/591099 images/color-profile-image-filter-all.html [ Failure ]
 crbug.com/591099 images/rendering-broken-block-flow-images.html [ Failure ]
 crbug.com/591099 images/rendering-broken-images.html [ Failure ]
-crbug.com/714962 inspector-protocol/css/css-get-platform-fonts.js [ Failure ]
 crbug.com/591099 inspector-protocol/dom-snapshot/dom-snapshot-getSnapshot-pseudo-element.js [ Failure ]
 crbug.com/591099 inspector-protocol/dom-snapshot/dom-snapshot-getSnapshot.js [ Failure ]
 crbug.com/714962 inspector-protocol/layout-fonts/languages-emoji-rare-glyphs.js [ Failure ]

third_party/WebKit/LayoutTests/flag-specific/enable-blink-features=LayoutNG/inspector-protocol/css/css-get-platform-fonts-expected.txt

+Test css.getPlatformFontsForNode method.
+
+Running test: testFirstLetterPseudoClass
+Font #0
+    name: <Some-family-name-0>
+    glyphCount: 29
+    isCustomFont: true
+Font #1
+    name: <Some-family-name-1>
+    glyphCount: 6
+    isCustomFont: false
+Font #2
+    name: <Some-family-name-2>
+    glyphCount: 1
+    isCustomFont: false
+
+Running test: testSelectElementPlatformFonts
+Font #0
+    name: <Some-family-name-0>
+    glyphCount: 27
+    isCustomFont: false
+

third_party/blink/renderer/core/inspector/inspector_css_agent.cc

@@ -1162,9 +1162,19 @@ Response InspectorCSSAgent::getComputedStyleForNode(
 
 void InspectorCSSAgent::CollectPlatformFontsForLayoutObject(
     LayoutObject* layout_object,
-    HashCountedSet<std::pair<int, String>>* font_stats) {
-  if (!layout_object->IsText())
+    HashCountedSet<std::pair<int, String>>* font_stats,
+    unsigned descendants_depth) {
+  if (!layout_object->IsText()) {
+    if (!descendants_depth)
+      return;
+    if (!layout_object->IsAnonymous())
+      --descendants_depth;
+    for (LayoutObject* child = layout_object->SlowFirstChild(); child;
+         child = child->NextSibling()) {
+      CollectPlatformFontsForLayoutObject(child, font_stats, descendants_depth);
+    }
     return;
+  }
 
   FontCachePurgePreventer preventer;
   LayoutText* layout_text = ToLayoutText(layout_object);
@@ -1214,15 +1224,9 @@ Response InspectorCSSAgent::getPlatformFontsForNode(
   HashCountedSet<std::pair<int, String>> font_stats;
   LayoutObject* root = node->GetLayoutObject();
   if (root) {
-    CollectPlatformFontsForLayoutObject(root, &font_stats);
     // Iterate upto two layers deep.
-    for (LayoutObject* child = root->SlowFirstChild(); child;
-         child = child->NextSibling()) {
-      CollectPlatformFontsForLayoutObject(child, &font_stats);
-      for (LayoutObject* child2 = child->SlowFirstChild(); child2;
-           child2 = child2->NextSibling())
-        CollectPlatformFontsForLayoutObject(child2, &font_stats);
-    }
+    const unsigned descendants_depth = 2;
+    CollectPlatformFontsForLayoutObject(root, &font_stats, descendants_depth);
   }
   *platform_fonts = protocol::Array<protocol::CSS::PlatformFontUsage>::create();
   for (auto& font : font_stats) {

third_party/blink/renderer/core/inspector/inspector_css_agent.h

@@ -274,7 +274,8 @@ class CORE_EXPORT InspectorCSSAgent final
 
   void CollectPlatformFontsForLayoutObject(
       LayoutObject*,
-      HashCountedSet<std::pair<int, String>>*);
+      HashCountedSet<std::pair<int, String>>*,
+      unsigned descendants_depth);
 
   InspectorStyleSheet* BindStyleSheet(CSSStyleSheet*);
   String UnbindStyleSheet(InspectorStyleSheet*);

third_party/blink/renderer/core/layout/layout_block_flow.cc

@@ -3140,7 +3140,8 @@ void LayoutBlockFlow::AddChild(LayoutObject* new_child,
         after_child->AddChild(new_child);
         return;
       }
-      LayoutInline* new_wrapper = LayoutInline::CreateAnonymous(&GetDocument());
+      LayoutInline* new_wrapper =
+          LayoutInline::CreateAnonymousForFirstLine(&GetDocument());
       new_wrapper->SetStyle(ComputedStyle::CreateAnonymousStyleWithDisplay(
           StyleRef(), EDisplay::kInline));
       LayoutBox::AddChild(new_wrapper, before_child);

third_party/blink/renderer/core/layout/layout_inline.cc

@@ -91,9 +91,21 @@ LayoutInline* LayoutInline::CreateAnonymous(Document* document) {
 }
 
 bool LayoutInline::IsFirstLineAnonymous() const {
-  // TODO(kojii): We can add a flag, but this seems enough for now.
-  return IsAnonymous() && Parent() && Parent()->IsLayoutBlockFlow() &&
-         !PreviousSibling() && !NextSibling();
+  return false;
+}
+
+// A private class to distinguish anonymous inline box for ::first-line from
+// other inline boxes.
+class LayoutInlineForFirstLine : public LayoutInline {
+ public:
+  LayoutInlineForFirstLine(Element* element) : LayoutInline(element) {}
+  bool IsFirstLineAnonymous() const final { return true; }
+};
+
+LayoutInline* LayoutInline::CreateAnonymousForFirstLine(Document* document) {
+  LayoutInline* layout_inline = new LayoutInlineForFirstLine(nullptr);
+  layout_inline->SetDocumentForAnonymous(document);
+  return layout_inline;
 }
 
 void LayoutInline::WillBeDestroyed() {

third_party/blink/renderer/core/layout/layout_inline.h

@@ -119,6 +119,10 @@ class CORE_EXPORT LayoutInline : public LayoutBoxModelObject {
 
   static LayoutInline* CreateAnonymous(Document*);
 
+  // Create an anonymous inline box for ::first-line. The instance created by
+  // this function has IsFirstLineAnonymous() == true.
+  static LayoutInline* CreateAnonymousForFirstLine(Document*);
+
   LayoutObject* FirstChild() const {
     DCHECK_EQ(Children(), VirtualChildren());
     return Children()->FirstChild();
@@ -141,7 +145,7 @@ class CORE_EXPORT LayoutInline : public LayoutBoxModelObject {
 
   // True if this is an anonymous inline box for ::first-line that wraps the
   // whole inline formatting context.
-  bool IsFirstLineAnonymous() const;
+  virtual bool IsFirstLineAnonymous() const;
 
   LayoutUnit MarginLeft() const final;
   LayoutUnit MarginRight() const final;