1 files changed, 58 insertions, 16 deletions

diff --git a/chromium/third_party/blink/renderer/platform/fonts/font_fallback_list.cc b/chromium/third_party/blink/renderer/platform/fonts/font_fallback_list.cc
index fa1a455e591..d00d18310bb 100644
--- a/chromium/third_party/blink/renderer/platform/fonts/font_fallback_list.cc
+++ b/chromium/third_party/blink/renderer/platform/fonts/font_fallback_list.cc
@@ -39,22 +39,24 @@
 
 namespace blink {
 
-FontFallbackList::FontFallbackList()
+FontFallbackList::FontFallbackList(FontSelector* font_selector)
     : cached_primary_simple_font_data_(nullptr),
-      font_selector_(nullptr),
-      font_selector_version_(0),
+      font_selector_(font_selector),
+      font_selector_version_(font_selector ? font_selector->Version() : 0),
       family_index_(0),
       generation_(FontCache::GetFontCache()->Generation()),
-      has_loading_fallback_(false) {}
+      has_loading_fallback_(false),
+      can_shape_word_by_word_(false),
+      can_shape_word_by_word_computed_(false) {}
 
-void FontFallbackList::Invalidate(FontSelector* font_selector) {
+void FontFallbackList::Invalidate() {
   ReleaseFontData();
   font_list_.clear();
   cached_primary_simple_font_data_ = nullptr;
   family_index_ = 0;
   has_loading_fallback_ = false;
-  if (font_selector_ != font_selector)
-    font_selector_ = font_selector;
+  can_shape_word_by_word_ = false;
+  can_shape_word_by_word_computed_ = false;
   font_selector_version_ = font_selector_ ? font_selector_->Version() : 0;
   generation_ = FontCache::GetFontCache()->Generation();
 }
@@ -65,13 +67,18 @@ void FontFallbackList::ReleaseFontData() {
     if (!font_list_[i]->IsCustomFont()) {
       DCHECK(!font_list_[i]->IsSegmented());
       FontCache::GetFontCache()->ReleaseFontData(
-          ToSimpleFontData(font_list_[i]));
+          To<SimpleFontData>(font_list_[i].get()));
     }
   }
   shape_cache_.reset();  // Clear the weak pointer to the cache instance.
 }
 
 bool FontFallbackList::LoadingCustomFonts() const {
+  // This function is only used for style and layout invalidation purposes. We
+  // don't need it for invalidation when the feature below is enabled.
+  if (RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled())
+    return false;
+
   if (!has_loading_fallback_)
     return false;
 
@@ -84,6 +91,8 @@ bool FontFallbackList::LoadingCustomFonts() const {
 }
 
 bool FontFallbackList::ShouldSkipDrawing() const {
+  DCHECK(IsValid());
+
   if (!has_loading_fallback_)
     return false;
 
@@ -96,7 +105,7 @@ bool FontFallbackList::ShouldSkipDrawing() const {
 }
 
 const SimpleFontData* FontFallbackList::DeterminePrimarySimpleFontData(
-    const FontDescription& font_description) const {
+    const FontDescription& font_description) {
   bool should_load_custom_font = true;
 
   for (unsigned font_index = 0;; ++font_index) {
@@ -114,8 +123,8 @@ const SimpleFontData* FontFallbackList::DeterminePrimarySimpleFontData(
       return last_resort_fallback;
     }
 
-    if (font_data->IsSegmented() &&
-        !ToSegmentedFontData(font_data)->ContainsCharacter(kSpaceCharacter))
+    const auto* segmented = DynamicTo<SegmentedFontData>(font_data);
+    if (segmented && !segmented->ContainsCharacter(kSpaceCharacter))
       continue;
 
     const SimpleFontData* font_data_for_space =
@@ -128,8 +137,7 @@ const SimpleFontData* FontFallbackList::DeterminePrimarySimpleFontData(
     if (!font_data_for_space->IsLoadingFallback())
       return font_data_for_space;
 
-    if (font_data->IsSegmented()) {
-      const SegmentedFontData* segmented = ToSegmentedFontData(font_data);
+    if (segmented) {
       for (unsigned i = 0; i < segmented->NumFaces(); i++) {
         const SimpleFontData* range_font_data =
             segmented->FaceAt(i)->FontData();
@@ -212,8 +220,9 @@ FallbackListCompositeKey FontFallbackList::CompositeKey(
       if (result) {
         bool is_unique_match = false;
         key.Add(font_description.CacheKey(params, is_unique_match));
-        if (!result->IsSegmented() && !result->IsCustomFont())
-          FontCache::GetFontCache()->ReleaseFontData(ToSimpleFontData(result));
+        auto* font_data = DynamicTo<SimpleFontData>(result.get());
+        if (!font_data && !result->IsCustomFont())
+          FontCache::GetFontCache()->ReleaseFontData(font_data);
       }
     }
     current_family = current_family->Next();
@@ -224,7 +233,12 @@ FallbackListCompositeKey FontFallbackList::CompositeKey(
 
 const FontData* FontFallbackList::FontDataAt(
     const FontDescription& font_description,
-    unsigned realized_font_index) const {
+    unsigned realized_font_index) {
+  if (RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled()) {
+    if (!IsValid())
+      Invalidate();
+  }
+
   // This fallback font is already in our list.
   if (realized_font_index < font_list_.size())
     return font_list_[realized_font_index].get();
@@ -250,6 +264,34 @@ const FontData* FontFallbackList::FontDataAt(
   return result.get();
 }
 
+bool FontFallbackList::ComputeCanShapeWordByWord(
+    const FontDescription& font_description) {
+  if (!font_description.GetTypesettingFeatures())
+    return true;
+
+  const SimpleFontData* primary_font = PrimarySimpleFontData(font_description);
+  if (!primary_font)
+    return false;
+
+  const FontPlatformData& platform_data = primary_font->PlatformData();
+  TypesettingFeatures features = font_description.GetTypesettingFeatures();
+  return !platform_data.HasSpaceInLigaturesOrKerning(features);
+}
+
+bool FontFallbackList::CanShapeWordByWord(
+    const FontDescription& font_description) {
+  if (RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled()) {
+    if (!IsValid())
+      Invalidate();
+  }
+
+  if (!can_shape_word_by_word_computed_) {
+    can_shape_word_by_word_ = ComputeCanShapeWordByWord(font_description);
+    can_shape_word_by_word_computed_ = true;
+  }
+  return can_shape_word_by_word_;
+}
+
 bool FontFallbackList::IsValid() const {
   if (!font_selector_)
     return font_selector_version_ == 0;