PlzNavigate: Move navigation-level mixed content checks to the browser.

content/shell/browser/layout_test/blink_test_controller.h

Index: content/shell/browser/layout_test/blink_test_controller.h
diff --git a/content/shell/browser/layout_test/blink_test_controller.h b/content/shell/browser/layout_test/blink_test_controller.h
index 45fb8898fff0366d816193332a7c0abb2e753d86..cdb8682d5c512b87be4270aaeac9a532907044c7 100644
--- a/content/shell/browser/layout_test/blink_test_controller.h
+++ b/content/shell/browser/layout_test/blink_test_controller.h
@@ -180,6 +180,11 @@ class BlinkTestController : public base::NonThreadSafe,
   // GpuDataManagerObserver implementation.
   void OnGpuProcessCrashed(base::TerminationStatus exit_code) override;
 
+  const base::DictionaryValue& accumulated_layout_test_runtime_flags_changes()
+      const {
+    return accumulated_layout_test_runtime_flags_changes_;
+  }
+
  private:
   enum TestPhase {
     BETWEEN_TESTS,