Instantiate Android system fonts with Fontations

After Julia landed [1] (thank you!), it's now possible to create
Fontations Android system fonts.

Create a base feature "FontationsAndroidSystemFonts" to set the Android
default font manager to one that instantiates through Fontations.

In the first patchset/upload, enable the feature by default to do one
round of testing on bots.

[1] https://chromium.googlesource.com/skia.git/+/eb9fc76e302f873de982cefa7690443e7a2cede5

Bug: chromium:370816214
Change-Id: Ieee9828fd5569289e726a45211c489c25e99a2aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6079955
Commit-Queue: Dominik Röttsches <drott@chromium.org>
Auto-Submit: Dominik Röttsches <drott@chromium.org>
Reviewed-by: Ben Wagner <bungeman@google.com>
Cr-Commit-Position: refs/heads/main@{#1435391}

skia/ext/font_utils.cc

@@ -14,6 +14,7 @@
 
 #if BUILDFLAG(IS_ANDROID)
 #include "third_party/skia/include/ports/SkFontMgr_android.h"
+#include "third_party/skia/include/ports/SkFontScanner_Fontations.h"
 #endif
 
 #if BUILDFLAG(IS_APPLE)
@@ -59,7 +60,11 @@ static sk_sp<SkFontMgr> fontmgr_factory() {
     return sk_ref_sp(g_fontmgr_override);
   }
 #if BUILDFLAG(IS_ANDROID)
-  return SkFontMgr_New_Android(nullptr);
+  if (base::FeatureList::IsEnabled(skia::kFontationsAndroidSystemFonts)) {
+    return SkFontMgr_New_Android(nullptr, SkFontScanner_Make_Fontations());
+  } else {
+    return SkFontMgr_New_Android(nullptr);
+  }
 #elif BUILDFLAG(IS_APPLE)
   return SkFontMgr_New_CoreText(nullptr);
 #elif BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_LINUX)

skia/fontations_feature.cc

@@ -11,4 +11,10 @@ BASE_FEATURE(kFontationsLinuxSystemFonts,
              "FontationsLinuxSystemFonts",
              base::FEATURE_ENABLED_BY_DEFAULT);
 
+// Instantiate system fonts on Android with Fontations, affects
+// SkFontMgr instantiation in skia/ext/font_utils.cc
+BASE_FEATURE(kFontationsAndroidSystemFonts,
+             "FontationsAndroidSystemFonts",
+             base::FEATURE_ENABLED_BY_DEFAULT);
+
 }  // namespace skia

skia/fontations_feature.h

@@ -12,6 +12,7 @@ namespace skia {
 
 SK_API BASE_DECLARE_FEATURE(kFontationsLinuxSystemFonts);
 
+SK_API BASE_DECLARE_FEATURE(kFontationsAndroidSystemFonts);
 }
 
 #endif  // SKIA_FONTATIONS_FEATURE_H_