Temporarily exclude extension_tab_util impl

chrome/browser/extensions/BUILD.gn

Index: chrome/browser/extensions/BUILD.gn
diff --git a/chrome/browser/extensions/BUILD.gn b/chrome/browser/extensions/BUILD.gn
index 6f4af634ce56f218031536ba39efec3f5137d26a..23a015b9ae000bb5132364299aa94854a57f4328 100644
--- a/chrome/browser/extensions/BUILD.gn
+++ b/chrome/browser/extensions/BUILD.gn
@@ -104,6 +104,16 @@ static_library("extensions") {
       "api/tabs/ash_panel_contents.h",
     ]
   }
+  if (use_athena) {
+    defines += [ USE_ATHENA ]
+    sources += rebase_path(
+      gypi_values.chrome_browser_extensions_athena_sources,
+        ".", "//chrome")
+  } else {
+    sources += rebase_path(
+      gypi_values.chrome_browser_extensions_non_athena_sources,
+        ".", "//chrome")
+  }
 
   if (is_linux) {
     configs += [ "//build/config/linux:fontconfig" ]