Remove command line/field trial support and configs for Isolate Extensions.

chrome/renderer/extensions/chrome_extensions_renderer_client.cc

Index: chrome/renderer/extensions/chrome_extensions_renderer_client.cc
diff --git a/chrome/renderer/extensions/chrome_extensions_renderer_client.cc b/chrome/renderer/extensions/chrome_extensions_renderer_client.cc
index 8a79ab62010f8f0bc4136c86b17779044b905a30..b1127e949e6dfdc908f093ff19dcd69512884b8a 100644
--- a/chrome/renderer/extensions/chrome_extensions_renderer_client.cc
+++ b/chrome/renderer/extensions/chrome_extensions_renderer_client.cc
@@ -77,8 +77,7 @@ bool CrossesExtensionExtents(blink::WebLocalFrame* frame,
 
     // We want to compare against the URL that determines the type of
     // process.  Use the URL of the opener's local frame root, which will
-    // correctly handle any site isolation modes (--site-per-process and
-    // --isolate-extensions).
+    // correctly handle any site isolation modes (e.g. --site-per-process).
     blink::WebLocalFrame* local_root = opener_frame->LocalRoot();
     old_url = local_root->GetDocument().Url();