feat: add 'disableHtmlFullscreenWindowResize' option to webPreferences (#17203)

This option allows users to prevent the window from resizing when the HTML5 FullScreen API is used.

atom/browser/common_web_contents_delegate.cc

@@ -619,7 +619,17 @@ void CommonWebContentsDelegate::SetHtmlApiFullscreen(bool enter_fullscreen) {
     return;
   }
 
-  owner_window_->SetFullScreen(enter_fullscreen);
+  // Set fullscreen on window if allowed.
+  auto* web_preferences = WebContentsPreferences::From(GetWebContents());
+  bool html_fullscreenable =
+      web_preferences ? !web_preferences->IsEnabled(
+                            options::kDisableHtmlFullscreenWindowResize)
+                      : true;
+
+  if (html_fullscreenable) {
+    owner_window_->SetFullScreen(enter_fullscreen);
+  }
+
   html_fullscreen_ = enter_fullscreen;
   native_fullscreen_ = false;
 }

atom/browser/web_contents_preferences.cc

@@ -122,6 +122,7 @@ WebContentsPreferences::WebContentsPreferences(
   SetDefaultBoolIfUndefined(options::kNodeIntegration, false);
   SetDefaultBoolIfUndefined(options::kNodeIntegrationInSubFrames, false);
   SetDefaultBoolIfUndefined(options::kNodeIntegrationInWorker, false);
+  SetDefaultBoolIfUndefined(options::kDisableHtmlFullscreenWindowResize, false);
   SetDefaultBoolIfUndefined(options::kWebviewTag, false);
   SetDefaultBoolIfUndefined(options::kSandbox, false);
   SetDefaultBoolIfUndefined(options::kNativeWindowOpen, false);
@@ -371,6 +372,9 @@ void WebContentsPreferences::AppendCommandLineSwitches(
   if (IsEnabled(options::kNodeIntegrationInSubFrames))
     command_line->AppendSwitch(switches::kNodeIntegrationInSubFrames);
 
+  if (IsEnabled(options::kDisableHtmlFullscreenWindowResize))
+    command_line->AppendSwitch(switches::kDisableHtmlFullscreenWindowResize);
+
   // We are appending args to a webContents so let's save the current state
   // of our preferences object so that during the lifetime of the WebContents
   // we can fetch the options used to initally configure the WebContents

atom/common/options_switches.cc

@@ -156,6 +156,10 @@ const char kOffscreen[] = "offscreen";
 
 const char kNodeIntegrationInSubFrames[] = "nodeIntegrationInSubFrames";
 
+// Disable window resizing when HTML Fullscreen API is activated.
+const char kDisableHtmlFullscreenWindowResize[] =
+    "disableHtmlFullscreenWindowResize";
+
 }  // namespace options
 
 namespace switches {
@@ -220,6 +224,10 @@ const char kNodeIntegrationInWorker[] = "node-integration-in-worker";
 // environments will be created in sub-frames.
 const char kNodeIntegrationInSubFrames[] = "node-integration-in-subframes";
 
+// Disable window resizing when HTML Fullscreen API is activated.
+const char kDisableHtmlFullscreenWindowResize[] =
+    "disable-html-fullscreen-window-resize";
+
 // Widevine options
 // Path to Widevine CDM binaries.
 const char kWidevineCdmPath[] = "widevine-cdm-path";

atom/common/options_switches.h

@@ -76,6 +76,7 @@ extern const char kWebSecurity[];
 extern const char kAllowRunningInsecureContent[];
 extern const char kOffscreen[];
 extern const char kNodeIntegrationInSubFrames[];
+extern const char kDisableHtmlFullscreenWindowResize[];
 
 }  // namespace options
 
@@ -111,6 +112,7 @@ extern const char kNativeWindowOpen[];
 extern const char kNodeIntegrationInWorker[];
 extern const char kWebviewTag[];
 extern const char kNodeIntegrationInSubFrames[];
+extern const char kDisableHtmlFullscreenWindowResize[];
 
 extern const char kWidevineCdmPath[];
 extern const char kWidevineCdmVersion[];

docs/api/browser-window.md

@@ -379,6 +379,9 @@ It creates a new `BrowserWindow` with native properties as set by the `options`.
       content in the window, can be `no-user-gesture-required`,
       `user-gesture-required`, `document-user-activation-required`. Defaults to
       `no-user-gesture-required`.
+    * `disableHtmlFullscreenWindowResize` Boolean (optional) - Whether to
+      prevent the window from resizing when entering HTML Fullscreen. Default
+      is `false`.
 
 When setting minimum or maximum window size with `minWidth`/`maxWidth`/
 `minHeight`/`maxHeight`, it only constrains the users. It won't prevent you from

docs/api/web-contents.md

@@ -361,6 +361,14 @@ win.webContents.on('before-input-event', (event, input) => {
 })
 ```
 
+#### Event: 'enter-html-full-screen'
+
+Emitted when the window enters a full-screen state triggered by HTML API.
+
+#### Event: 'leave-html-full-screen'
+
+Emitted when the window leaves a full-screen state triggered by HTML API.
+
 #### Event: 'devtools-opened'
 
 Emitted when DevTools is opened.

spec/api-browser-window-spec.js

@@ -2097,6 +2097,28 @@ describe('BrowserWindow module', () => {
         expect(typeofProcess).to.eql('undefined')
       })
     })
+
+    describe('"disableHtmlFullscreenWindowResize" option', () => {
+      it('prevents window from resizing when set', (done) => {
+        w.destroy()
+        w = new BrowserWindow({
+          show: false,
+          webPreferences: {
+            disableHtmlFullscreenWindowResize: true
+          }
+        })
+        w.webContents.once('did-finish-load', () => {
+          const size = w.getSize()
+          w.webContents.once('enter-html-full-screen', () => {
+            const newSize = w.getSize()
+            expect(newSize).to.deep.equal(size)
+            done()
+          })
+          w.webContents.executeJavaScript('document.body.webkitRequestFullscreen()', true)
+        })
+        w.loadURL('about:blank')
+      })
+    })
   })
 
   describe('nativeWindowOpen + contextIsolation options', () => {