feat: expose setBackgroundThrottling api (#15104)

atom/browser/api/atom_api_web_contents.cc

@@ -1104,6 +1104,37 @@ void WebContents::NavigationEntryCommitted(
        details.is_same_document, details.did_replace_entry);
 }
 
+void WebContents::SetBackgroundThrottling(bool allowed) {
+  background_throttling_ = allowed;
+
+  const auto* contents = web_contents();
+  if (!contents) {
+    return;
+  }
+
+  const auto* render_view_host = contents->GetRenderViewHost();
+  if (!render_view_host) {
+    return;
+  }
+
+  const auto* render_process_host = render_view_host->GetProcess();
+  if (!render_process_host) {
+    return;
+  }
+
+  auto* render_widget_host_impl = content::RenderWidgetHostImpl::FromID(
+      render_process_host->GetID(), render_view_host->GetRoutingID());
+  if (!render_widget_host_impl) {
+    return;
+  }
+
+  render_widget_host_impl->disable_hidden_ = !background_throttling_;
+
+  if (render_widget_host_impl->is_hidden()) {
+    render_widget_host_impl->WasShown(false);
+  }
+}
+
 int WebContents::GetProcessID() const {
   return web_contents()->GetMainFrame()->GetProcess()->GetID();
 }
@@ -2011,6 +2042,8 @@ void WebContents::BuildPrototype(v8::Isolate* isolate,
   prototype->SetClassName(mate::StringToV8(isolate, "WebContents"));
   mate::ObjectTemplateBuilder(isolate, prototype->PrototypeTemplate())
       .MakeDestroyable()
+      .SetMethod("setBackgroundThrottling",
+                 &WebContents::SetBackgroundThrottling)
       .SetMethod("getProcessId", &WebContents::GetProcessID)
       .SetMethod("getOSProcessId", &WebContents::GetOSProcessID)
       .SetMethod("equal", &WebContents::Equal)

atom/browser/api/atom_api_web_contents.h

@@ -101,6 +101,7 @@ class WebContents : public mate::TrackableObject<WebContents>,
   // Notifies to destroy any guest web contents before destroying self.
   void DestroyWebContents(bool async);
 
+  void SetBackgroundThrottling(bool allowed);
   int GetProcessID() const;
   base::ProcessId GetOSProcessID() const;
   Type GetType() const;

docs/api/web-contents.md

@@ -1527,6 +1527,13 @@ Returns `Promise<void>` - Indicates whether the snapshot has been created succes
 
 Takes a V8 heap snapshot and saves it to `filePath`.
 
+#### `contents.setBackgroundThrottling(allowed)`
+
+* `allowed` Boolean
+
+Controls whether or not this WebContents will throttle animations and timers
+when the page becomes backgrounded. This also affects the Page Visibility API.
+
 ### Instance Properties
 
 #### `contents.id`

lib/browser/api/browser-window.js

@@ -221,6 +221,9 @@ Object.assign(BrowserWindow.prototype, {
   },
   setTouchBar (touchBar) {
     electron.TouchBar._setOnWindow(touchBar, this)
+  },
+  setBackgroundThrottling (allowed) {
+    this.webContents.setBackgroundThrottling(allowed)
   }
 })
 

spec/api-web-contents-spec.js

@@ -905,4 +905,31 @@ describe('webContents module', () => {
       return expect(promise).to.be.eventually.rejectedWith(Error, 'takeHeapSnapshot failed')
     })
   })
+
+  describe('setBackgroundThrottling()', () => {
+    it('does not crash when allowing', (done) => {
+      w.webContents.setBackgroundThrottling(true)
+      done()
+    })
+
+    it('does not crash when disallowing', (done) => {
+      w.destroy()
+      w = new BrowserWindow({
+        show: false,
+        width: 400,
+        height: 400,
+        webPreferences: {
+          backgroundThrottling: true
+        }
+      })
+
+      w.webContents.setBackgroundThrottling(false)
+      done()
+    })
+
+    it('does not crash when called via BrowserWindow', (done) => {
+      w.setBackgroundThrottling(true)
+      done()
+    })
+  })
 })