fix: defaultFontFamily in webPreferences (#37863)

* fix: defaultFontFamily in webPreferences

* chore: check if default_font_family_ is empty

shell/browser/web_contents_preferences.cc

@@ -425,24 +425,30 @@ void WebContentsPreferences::OverrideWebkitPrefs(
   prefs->web_security_enabled = web_security_;
   prefs->allow_running_insecure_content = allow_running_insecure_content_;
 
-  if (auto font =
-          default_font_family_.find("standard") != default_font_family_.end())
-    prefs->standard_font_family_map[blink::web_pref::kCommonScript] = font;
-  if (auto font =
-          default_font_family_.find("serif") != default_font_family_.end())
-    prefs->serif_font_family_map[blink::web_pref::kCommonScript] = font;
-  if (auto font =
-          default_font_family_.find("sansSerif") != default_font_family_.end())
-    prefs->sans_serif_font_family_map[blink::web_pref::kCommonScript] = font;
-  if (auto font =
-          default_font_family_.find("monospace") != default_font_family_.end())
-    prefs->fixed_font_family_map[blink::web_pref::kCommonScript] = font;
-  if (auto font =
-          default_font_family_.find("cursive") != default_font_family_.end())
-    prefs->cursive_font_family_map[blink::web_pref::kCommonScript] = font;
-  if (auto font =
-          default_font_family_.find("fantasy") != default_font_family_.end())
-    prefs->fantasy_font_family_map[blink::web_pref::kCommonScript] = font;
+  if (!default_font_family_.empty()) {
+    if (auto iter = default_font_family_.find("standard");
+        iter != default_font_family_.end())
+      prefs->standard_font_family_map[blink::web_pref::kCommonScript] =
+          iter->second;
+    if (auto iter = default_font_family_.find("serif");
+        iter != default_font_family_.end())
+      prefs->serif_font_family_map[blink::web_pref::kCommonScript] = iter->second;
+    if (auto iter = default_font_family_.find("sansSerif");
+        iter != default_font_family_.end())
+      prefs->sans_serif_font_family_map[blink::web_pref::kCommonScript] =
+          iter->second;
+    if (auto iter = default_font_family_.find("monospace");
+        iter != default_font_family_.end())
+      prefs->fixed_font_family_map[blink::web_pref::kCommonScript] = iter->second;
+    if (auto iter = default_font_family_.find("cursive");
+        iter != default_font_family_.end())
+      prefs->cursive_font_family_map[blink::web_pref::kCommonScript] =
+          iter->second;
+    if (auto iter = default_font_family_.find("fantasy");
+        iter != default_font_family_.end())
+      prefs->fantasy_font_family_map[blink::web_pref::kCommonScript] =
+          iter->second;
+  }
 
   if (default_font_size_)
     prefs->default_font_size = *default_font_size_;

spec/api-browser-window-spec.ts

@@ -3867,6 +3867,22 @@ describe('BrowserWindow module', () => {
         expect(w.getSize()).to.deep.equal(size);
       });
     });
+
+    describe('"defaultFontFamily" option', () => {
+      it('can change the standard font family', async () => {
+        const w = new BrowserWindow({
+          show: false,
+          webPreferences: {
+            defaultFontFamily: {
+              standard: 'Impact'
+            }
+          }
+        });
+        await w.loadFile(path.join(fixtures, 'pages', 'content.html'));
+        const fontFamily = await w.webContents.executeJavaScript("window.getComputedStyle(document.getElementsByTagName('p')[0])['font-family']", true);
+        expect(fontFamily).to.equal('Impact');
+      });
+    });
   });
 
   describe('beforeunload handler', function () {