Slightly refactor FontFallbackList invalidation

Since all access to FontFallbackList needs to go through Font, this
patch moves the call site of FontFallbackList::Invalidate() up into
Font::EnsureFontFallbackList() to make it simpler.

Bug: 441925
Change-Id: I1515ae4f76f528f7f395135c1cf799cff5106f6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2146062
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758473}

third_party/blink/renderer/platform/fonts/font.h

@@ -244,6 +244,10 @@ class PLATFORM_EXPORT Font {
   FontFallbackList* EnsureFontFallbackList() const {
     if (!font_fallback_list_)
       font_fallback_list_ = FontFallbackList::Create(nullptr);
+    if (RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled()) {
+      if (!font_fallback_list_->IsValid())
+        font_fallback_list_->Invalidate();
+    }
     return font_fallback_list_.get();
   }
 

third_party/blink/renderer/platform/fonts/font_fallback_list.cc

@@ -50,6 +50,7 @@ FontFallbackList::FontFallbackList(FontSelector* font_selector)
       can_shape_word_by_word_computed_(false) {}
 
 void FontFallbackList::Invalidate() {
+  DCHECK(RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled());
   ReleaseFontData();
   font_list_.clear();
   cached_primary_simple_font_data_ = nullptr;
@@ -234,11 +235,6 @@ FallbackListCompositeKey FontFallbackList::CompositeKey(
 const FontData* FontFallbackList::FontDataAt(
     const FontDescription& font_description,
     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();
@@ -280,11 +276,6 @@ bool FontFallbackList::ComputeCanShapeWordByWord(
 
 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;

third_party/blink/renderer/platform/fonts/font_fallback_list.h

@@ -60,11 +60,6 @@ class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
   uint16_t Generation() const { return generation_; }
 
   ShapeCache* GetShapeCache(const FontDescription& font_description) {
-    if (RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled()) {
-      if (!IsValid())
-        Invalidate();
-    }
-
     if (!shape_cache_) {
       FallbackListCompositeKey key = CompositeKey(font_description);
       shape_cache_ =
@@ -78,11 +73,6 @@ class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
 
   const SimpleFontData* PrimarySimpleFontData(
       const FontDescription& font_description) {
-    if (RuntimeEnabledFeatures::CSSReducedFontLoadingInvalidationsEnabled()) {
-      if (!IsValid())
-        Invalidate();
-    }
-
     if (!cached_primary_simple_font_data_) {
       cached_primary_simple_font_data_ =
           DeterminePrimarySimpleFontData(font_description);