Follow theme settings like Chrome does

Set Blink-settings based on Chromium theme settings to match Chrome
defaults.

Change-Id: I02975c319644583166ed3c5a0eae02975d7b14f1
Fixes: QTBUG-79347
Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io>

1 files changed, 46 insertions, 0 deletions

diff --git a/src/core/web_engine_settings.cpp b/src/core/web_engine_settings.cpp
index 9bc1279ba..49006ec20 100644
--- a/src/core/web_engine_settings.cpp
+++ b/src/core/web_engine_settings.cpp
@@ -53,7 +53,9 @@
 #include "content/public/common/webrtc_ip_handling_policy.h"
 #include "media/base/media_switches.h"
 #include "third_party/blink/public/mojom/renderer_preferences.mojom.h"
+#include "ui/base/ui_base_switches.h"
 #include "ui/events/event_switches.h"
+#include "ui/native_theme/native_theme.h"
 
 #include <QFont>
 #include <QTimer>
@@ -399,6 +401,50 @@ void WebEngineSettings::applySettingsToWebPreferences(content::WebPreferences *p
     prefs->minimum_font_size = fontSize(MinimumFontSize);
     prefs->minimum_logical_font_size = fontSize(MinimumLogicalFontSize);
     prefs->default_encoding = defaultTextEncoding().toStdString();
+
+    // Set the theme colors. Based on chrome_content_browser_client.cc:
+    const ui::NativeTheme *webTheme = ui::NativeTheme::GetInstanceForWeb();
+    if (webTheme) {
+#if !defined(OS_MACOSX)
+        // Mac has a concept of high contrast that does not relate to forced colors.
+        prefs->forced_colors = webTheme->UsesHighContrastColors()
+                                   ? blink::ForcedColors::kActive
+                                   : blink::ForcedColors::kNone;
+#endif  // !defined(OS_MACOSX)
+        switch (webTheme->GetPreferredColorScheme()) {
+          case ui::NativeTheme::PreferredColorScheme::kDark:
+            prefs->preferred_color_scheme = blink::PreferredColorScheme::kDark;
+            break;
+          case ui::NativeTheme::PreferredColorScheme::kLight:
+            prefs->preferred_color_scheme = blink::PreferredColorScheme::kLight;
+            break;
+          case ui::NativeTheme::PreferredColorScheme::kNoPreference:
+            prefs->preferred_color_scheme = blink::PreferredColorScheme::kNoPreference;
+        }
+    }
+
+    // Apply native CaptionStyle parameters.
+    base::Optional<ui::CaptionStyle> style;
+    if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kForceCaptionStyle)) {
+        style = ui::CaptionStyle::FromSpec(
+                    base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(switches::kForceCaptionStyle));
+    }
+
+    // Apply system caption style.
+    if (!style && webTheme)
+        style = webTheme->GetSystemCaptionStyle();
+
+    if (style) {
+        prefs->text_track_background_color = style->background_color;
+        prefs->text_track_text_color = style->text_color;
+        prefs->text_track_text_size = style->text_size;
+        prefs->text_track_text_shadow = style->text_shadow;
+        prefs->text_track_font_family = style->font_family;
+        prefs->text_track_font_variant = style->font_variant;
+        prefs->text_track_window_color = style->window_color;
+        prefs->text_track_window_padding = style->window_padding;
+        prefs->text_track_window_radius = style->window_radius;
+    }
 }
 
 bool WebEngineSettings::applySettingsToRendererPreferences(blink::mojom::RendererPreferences *prefs)