chore: remove unused field `ElectronBrowserClient::browser_main_parts_` (#42966)

chore: remove unused field ElectronBrowserClient::browser_main_parts_

caller removed in 48d0b09a

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Charles Kerr <[email protected]>

shell/browser/electron_browser_client.cc

@@ -824,13 +824,7 @@ ElectronBrowserClient::GetSystemNetworkContext() {
 
 std::unique_ptr<content::BrowserMainParts>
 ElectronBrowserClient::CreateBrowserMainParts(bool /* is_integration_test */) {
-  auto browser_main_parts = std::make_unique<ElectronBrowserMainParts>();
-
-#if BUILDFLAG(IS_MAC)
-  browser_main_parts_ = browser_main_parts.get();
-#endif
-
-  return browser_main_parts;
+  return std::make_unique<ElectronBrowserMainParts>();
 }
 
 void ElectronBrowserClient::WebNotificationAllowed(

shell/browser/electron_browser_client.h

@@ -340,10 +340,6 @@ class ElectronBrowserClient : public content::ContentBrowserClient,
   std::unique_ptr<ElectronHidDelegate> hid_delegate_;
   std::unique_ptr<ElectronWebAuthenticationDelegate>
       web_authentication_delegate_;
-
-#if BUILDFLAG(IS_MAC)
-  raw_ptr<ElectronBrowserMainParts> browser_main_parts_ = nullptr;
-#endif
 };
 
 }  // namespace electron