[DevTools] Eliminate frameId and isContentScript from js protocol.

chrome/test/chromedriver/chrome/navigation_tracker.cc

Index: chrome/test/chromedriver/chrome/navigation_tracker.cc
diff --git a/chrome/test/chromedriver/chrome/navigation_tracker.cc b/chrome/test/chromedriver/chrome/navigation_tracker.cc
index 351f881526a6f24cbf7a5c135c842f29be05c74a..2089f9866530d256c7f4db4e7e488ffe8d782116 100644
--- a/chrome/test/chromedriver/chrome/navigation_tracker.cc
+++ b/chrome/test/chromedriver/chrome/navigation_tracker.cc
@@ -329,8 +329,11 @@ Status NavigationTracker::OnEvent(DevToolsClient* client,
       if (!params.GetInteger("context.id", &execution_context_id))
         return Status(kUnknownError, "missing or invalid 'context.id'");
       std::string frame_id;
-      if (!params.GetString("context.frameId", &frame_id))
-        return Status(kUnknownError, "missing or invalid 'context.frameId'");
+      if (!params.GetString("context.auxData.frameId", &frame_id)) {
+        // TODO(samuong): remove this when we stop supporting Chrome 53.
+        if (!params.GetString("context.frameId", &frame_id))
+          return Status(kUnknownError, "missing or invalid 'context.frameId'");
+      }
       if (frame_id == dummy_frame_id_)
         dummy_execution_context_id_ = execution_context_id;
       else