feat: Add option to conditionally disable site instance patches (#18396)

* chore: allow conditional disable of the site instance override patches at runtime

* feat: add app.allowRendererProcessReuse property to allow runtime disable of site instance overrides

spec: add tests for the new allowRendererProcessReuse property

feat: add console warnings / errors for loading non context-aware native modules
  * Only error if the patch is disabled
  * Warn all the time, this will ship in Electron 7

atom/browser/api/atom_api_app.cc

@@ -1286,6 +1286,13 @@ std::string App::GetUserAgentFallback() {
   return AtomBrowserClient::Get()->GetUserAgent();
 }
 
+void App::SetBrowserClientCanUseCustomSiteInstance(bool should_disable) {
+  AtomBrowserClient::Get()->SetCanUseCustomSiteInstance(should_disable);
+}
+bool App::CanBrowserClientUseCustomSiteInstance() {
+  return AtomBrowserClient::Get()->CanUseCustomSiteInstance();
+}
+
 #if defined(OS_MACOSX)
 bool App::MoveToApplicationsFolder(mate::Arguments* args) {
   return ui::cocoa::AtomBundleMover::Move(args);
@@ -1467,7 +1474,10 @@ void App::BuildPrototype(v8::Isolate* isolate,
 #endif
       .SetProperty("userAgentFallback", &App::GetUserAgentFallback,
                    &App::SetUserAgentFallback)
-      .SetMethod("enableSandbox", &App::EnableSandbox);
+      .SetMethod("enableSandbox", &App::EnableSandbox)
+      .SetProperty("allowRendererProcessReuse",
+                   &App::CanBrowserClientUseCustomSiteInstance,
+                   &App::SetBrowserClientCanUseCustomSiteInstance);
 }
 
 }  // namespace api

atom/browser/api/atom_api_app.h

@@ -213,6 +213,8 @@ class App : public AtomBrowserClient::Delegate,
   void EnableSandbox(mate::Arguments* args);
   void SetUserAgentFallback(const std::string& user_agent);
   std::string GetUserAgentFallback();
+  void SetBrowserClientCanUseCustomSiteInstance(bool should_disable);
+  bool CanBrowserClientUseCustomSiteInstance();
 
 #if defined(OS_MACOSX)
   bool MoveToApplicationsFolder(mate::Arguments* args);

atom/browser/atom_browser_client.cc

@@ -403,6 +403,14 @@ void AtomBrowserClient::OverrideWebkitPrefs(content::RenderViewHost* host,
     web_preferences->OverrideWebkitPrefs(prefs);
 }
 
+void AtomBrowserClient::SetCanUseCustomSiteInstance(bool should_disable) {
+  disable_process_restart_tricks_ = should_disable;
+}
+
+bool AtomBrowserClient::CanUseCustomSiteInstance() {
+  return disable_process_restart_tricks_;
+}
+
 content::ContentBrowserClient::SiteInstanceForNavigationType
 AtomBrowserClient::ShouldOverrideSiteInstanceForNavigation(
     content::RenderFrameHost* current_rfh,
@@ -509,6 +517,10 @@ void AtomBrowserClient::AppendExtraCommandLineSwitches(
       web_preferences->AppendCommandLineSwitches(command_line);
     SessionPreferences::AppendExtraCommandLineSwitches(
         web_contents->GetBrowserContext(), command_line);
+    if (CanUseCustomSiteInstance()) {
+      command_line->AppendSwitch(
+          switches::kDisableElectronSiteInstanceOverrides);
+    }
   }
 }
 

atom/browser/atom_browser_client.h

@@ -67,6 +67,9 @@ class AtomBrowserClient : public content::ContentBrowserClient,
   std::string GetUserAgent() const override;
   void SetUserAgent(const std::string& user_agent);
 
+  void SetCanUseCustomSiteInstance(bool should_disable);
+  bool CanUseCustomSiteInstance() override;
+
  protected:
   void RenderProcessWillLaunch(
       content::RenderProcessHost* host,
@@ -253,6 +256,8 @@ class AtomBrowserClient : public content::ContentBrowserClient,
 
   std::string user_agent_override_ = "";
 
+  bool disable_process_restart_tricks_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(AtomBrowserClient);
 };
 

atom/common/options_switches.cc

@@ -232,6 +232,8 @@ const char kScrollBounce[] = "scroll-bounce";
 const char kHiddenPage[] = "hidden-page";
 const char kNativeWindowOpen[] = "native-window-open";
 const char kWebviewTag[] = "webview-tag";
+const char kDisableElectronSiteInstanceOverrides[] =
+    "disable-electron-site-instance-overrides";
 
 // Command switch passed to renderer process to control nodeIntegration.
 const char kNodeIntegrationInWorker[] = "node-integration-in-worker";

atom/common/options_switches.h

@@ -118,6 +118,7 @@ extern const char kNodeIntegrationInWorker[];
 extern const char kWebviewTag[];
 extern const char kNodeIntegrationInSubFrames[];
 extern const char kDisableHtmlFullscreenWindowResize[];
+extern const char kDisableElectronSiteInstanceOverrides[];
 
 extern const char kWidevineCdmPath[];
 extern const char kWidevineCdmVersion[];

atom/renderer/atom_renderer_client.cc

@@ -104,6 +104,13 @@ void AtomRendererClient::DidCreateScriptContext(
 
   // Setup node environment for each window.
   node::Environment* env = node_bindings_->CreateEnvironment(context);
+  auto* command_line = base::CommandLine::ForCurrentProcess();
+  // If we have disabled the site instance overrides we should prevent loading
+  // any non-context aware native module
+  if (command_line->HasSwitch(switches::kDisableElectronSiteInstanceOverrides))
+    env->ForceOnlyContextAwareNativeModules();
+  env->WarnNonContextAwareNativeModules();
+
   environments_.insert(env);
 
   // Add Electron extended APIs.
@@ -145,9 +152,11 @@ void AtomRendererClient::WillReleaseScriptContext(
   // Destroy the node environment.  We only do this if node support has been
   // enabled for sub-frames to avoid a change-of-behavior / introduce crashes
   // for existing users.
-  // TODO(MarshallOfSOund): Free the environment regardless of this switch
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kNodeIntegrationInSubFrames))
+  // We also do this if we have disable electron site instance overrides to
+  // avoid memory leaks
+  auto* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kNodeIntegrationInSubFrames) ||
+      command_line->HasSwitch(switches::kDisableElectronSiteInstanceOverrides))
     node::FreeEnvironment(env);
 
   // ElectronBindings is tracking node environments.