Sandbox html_viewer on Linux.

components/html_viewer/BUILD.gn

Index: components/html_viewer/BUILD.gn
diff --git a/components/html_viewer/BUILD.gn b/components/html_viewer/BUILD.gn
index 484b96fd47e47573cd8c8141bd55fae1ed64af6f..2b848b5c416e5ccaa2270b03466486e06439ab0e 100644
--- a/components/html_viewer/BUILD.gn
+++ b/components/html_viewer/BUILD.gn
@@ -184,6 +184,10 @@ source_set("lib") {
     sources += [ "html_viewer_version.rc" ]
   }
 
+  if (is_linux && !is_android) {
+    deps += [ "//components/font_service/public/cpp" ]
+  }
+
   data_deps = [
     "//components/clipboard",
     "//components/view_manager",
@@ -315,4 +319,8 @@ mojo_native_application("apptests") {
     ":html_viewer",
     "//components/view_manager",
   ]
+
+  if (is_linux && !is_android) {
+    data_deps += [ "//components/font_service" ]
+  }
 }