webvtt: Add support for Windows system styling for captions

This change:
1) Adds 4 new properties to CaptionStyle.
2) Adds caption_style_win.cc that contains a Windows implementation for
   CaptionStyle::FromSystemSettings().
3) Adds a new feature flag to enable Windows system styling.
4) Follows the same pattern as the earlier change here:
   https://chromium-review.googlesource.com/c/chromium/src/+/1418399

Next steps:
Add support for background opacity, window opacity, and window color

Bug: 897730

Change-Id: Iefb0092c32b4fdb3d4d6412a2e21b9bdf018887f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1482140Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Rahul Singh <rahsin@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#638316}

chrome/browser/chrome_content_browser_client.cc

@@ -3326,6 +3326,10 @@ void ChromeContentBrowserClient::OverrideWebkitPrefs(
       ui::NativeTheme::GetInstanceForWeb()->GetSystemCaptionStyle();
   web_prefs->text_track_background_color = style.background_color;
   web_prefs->text_track_text_color = style.text_color;
+  web_prefs->text_track_text_size = style.text_size;
+  web_prefs->text_track_text_shadow = style.text_shadow;
+  web_prefs->text_track_font_family = style.font_family;
+  web_prefs->text_track_font_variant = style.font_variant;
 
   for (size_t i = 0; i < extra_parts_.size(); ++i)
     extra_parts_[i]->OverrideWebkitPrefs(rvh, web_prefs);

content/public/common/common_param_traits_macros.h

@@ -196,6 +196,10 @@ IPC_STRUCT_TRAITS_BEGIN(content::WebPreferences)
   IPC_STRUCT_TRAITS_MEMBER(text_track_background_color)
   IPC_STRUCT_TRAITS_MEMBER(text_track_margin_percentage)
   IPC_STRUCT_TRAITS_MEMBER(text_track_text_color)
+  IPC_STRUCT_TRAITS_MEMBER(text_track_text_size)
+  IPC_STRUCT_TRAITS_MEMBER(text_track_text_shadow)
+  IPC_STRUCT_TRAITS_MEMBER(text_track_font_family)
+  IPC_STRUCT_TRAITS_MEMBER(text_track_font_variant)
   IPC_STRUCT_TRAITS_MEMBER(text_autosizing_enabled)
   IPC_STRUCT_TRAITS_MEMBER(double_tap_to_zoom_enabled)
   IPC_STRUCT_TRAITS_MEMBER(web_app_scope)

content/public/common/web_preferences.h

@@ -206,6 +206,15 @@ struct CONTENT_EXPORT WebPreferences {
   std::string text_track_background_color;
   std::string text_track_text_color;
 
+  // These fields specify values for CSS properties used to style WebVTT text
+  // tracks.
+  // Specifies CSS font-size property in percentage.
+  std::string text_track_text_size;
+  std::string text_track_text_shadow;
+  std::string text_track_font_family;
+  // Specifies the value for CSS font-variant property.
+  std::string text_track_font_variant;
+
   // Specifies the margin for WebVTT text tracks as a percentage of media
   // element height/width (for horizontal/vertical text respectively).
   // Cues will not be placed in this margin area.

content/renderer/render_view_impl.cc

@@ -823,6 +823,14 @@ void RenderView::ApplyWebPreferences(const WebPreferences& prefs,
       WebString::FromASCII(prefs.text_track_background_color));
   settings->SetTextTrackTextColor(
       WebString::FromASCII(prefs.text_track_text_color));
+  settings->SetTextTrackTextSize(
+      WebString::FromASCII(prefs.text_track_text_size));
+  settings->SetTextTrackTextShadow(
+      WebString::FromASCII(prefs.text_track_text_shadow));
+  settings->SetTextTrackFontFamily(
+      WebString::FromASCII(prefs.text_track_font_family));
+  settings->SetTextTrackFontVariant(
+      WebString::FromASCII(prefs.text_track_font_variant));
   settings->SetTextTrackMarginPercentage(prefs.text_track_margin_percentage);
 
   // Needs to happen before SetDefaultPageScaleLimits below since that'll

ui/base/ui_base_features.cc

@@ -43,6 +43,10 @@ const base::Feature kSettingsShowsPerKeyboardSettings = {
 const base::Feature kInputMethodSettingsUiUpdate = {
     "InputMethodSettingsUiUpdate", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Allows system caption style for WebVTT Captions.
+const base::Feature kSystemCaptionStyle{"SystemCaptionStyle",
+                                        base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Allows system keyboard event capture via the keyboard lock API.
 const base::Feature kSystemKeyboardLock{"SystemKeyboardLock",
                                         base::FEATURE_ENABLED_BY_DEFAULT};

ui/base/ui_base_features.h

@@ -27,6 +27,8 @@ extern const base::Feature kSettingsShowsPerKeyboardSettings;
 COMPONENT_EXPORT(UI_BASE_FEATURES)
 extern const base::Feature kInputMethodSettingsUiUpdate;
 COMPONENT_EXPORT(UI_BASE_FEATURES)
+extern const base::Feature kSystemCaptionStyle;
+COMPONENT_EXPORT(UI_BASE_FEATURES)
 extern const base::Feature kSystemKeyboardLock;
 COMPONENT_EXPORT(UI_BASE_FEATURES)
 extern const base::Feature kNotificationIndicator;

ui/native_theme/BUILD.gn

@@ -10,6 +10,7 @@ jumbo_component("native_theme") {
   sources = [
     "caption_style.cc",
     "caption_style.h",
+    "caption_style_win.cc",
     "common_theme.cc",
     "common_theme.h",
     "native_theme.cc",
@@ -111,6 +112,10 @@ test("native_theme_unittests") {
     sources += [ "native_theme_mac_unittest.cc" ]
   }
 
+  if (is_win) {
+    sources += [ "caption_style_win_unittest.cc" ]
+  }
+
   deps = [
     ":native_theme",
     "//base/test:run_all_unittests",

ui/native_theme/caption_style.cc

@@ -3,9 +3,9 @@
 // found in the LICENSE file.
 
 #include "ui/native_theme/caption_style.h"
-
 #include "base/json/json_reader.h"
 #include "base/values.h"
+#include "build/build_config.h"
 
 namespace ui {
 
@@ -29,4 +29,10 @@ CaptionStyle CaptionStyle::FromSpec(const std::string& spec) {
   return style;
 }
 
+#if !defined(OS_WIN)
+CaptionStyle CaptionStyle::FromSystemSettings() {
+  return CaptionStyle();
+}
+#endif
+
 }  // namespace ui

ui/native_theme/caption_style.h

@@ -25,10 +25,18 @@ struct NATIVE_THEME_EXPORT CaptionStyle {
   // for testing.
   static CaptionStyle FromSpec(const std::string& spec);
 
+  // Returns a CaptionStyle populated from the System's Settings.
+  static CaptionStyle FromSystemSettings();
+
   std::string text_color;
   std::string background_color;
+  // Holds text size percentage as a css string.
+  std::string text_size;
+  std::string text_shadow;
+  std::string font_family;
+  std::string font_variant;
 };
 
 }  // namespace ui
 
-#endif
+#endif  // UI_NATIVE_THEME_CAPTION_STYLE_H_

ui/native_theme/caption_style_win.cc

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/native_theme/caption_style.h"
+
+#include <Windows.Media.ClosedCaptioning.h>
+#include <wrl/client.h>
+
+#include <string>
+
+#include "base/command_line.h"
+#include "base/trace_event/trace_event.h"
+#include "base/win/core_winrt_util.h"
+#include "base/win/windows_version.h"
+#include "ui/base/ui_base_features.h"
+
+namespace ui {
+
+using namespace ABI::Windows::Media::ClosedCaptioning;
+
+namespace {
+
+// This is used to add tracing when a COM call fails.
+// Param 1 - line is the line number in the caller. This helps locate
+// problematic code.
+// Param 2 - hr is the failure HRESULT.
+void LogCapStyleWinError(int line, HRESULT hr) {
+  TRACE_EVENT2("ui", "LogWindowsCaptionStyleError", "line", line, "hr", hr);
+}
+
+// Translates a Windows::Media::ClosedCaptioning::ClosedCaptionStyle to a
+// CSS FontFamily value.
+// These fonts were chosen to satisfy the characteristics represented by values
+// of ClosedCaptionStyle Enum in Windows Settings.
+void GetFontFamilyString(ClosedCaptionStyle closed_caption_style,
+                         std::string* css_font_family,
+                         std::string* css_font_variant) {
+  *css_font_variant = "normal";
+  switch (closed_caption_style) {
+    case ClosedCaptionStyle_MonospacedWithSerifs:
+      *css_font_family = "Courier New";
+      break;
+    case ClosedCaptionStyle_ProportionalWithSerifs:
+      *css_font_family = "Times New Roman";
+      break;
+    case ClosedCaptionStyle_MonospacedWithoutSerifs:
+      *css_font_family = "Consolas";
+      break;
+    case ClosedCaptionStyle_ProportionalWithoutSerifs:
+      *css_font_family = "Tahoma";
+      break;
+    case ClosedCaptionStyle_Casual:
+      *css_font_family = "Segoe Print";
+      break;
+    case ClosedCaptionStyle_Cursive:
+      *css_font_family = "Segoe Script";
+      break;
+    case ClosedCaptionStyle_SmallCapitals:
+      *css_font_family = "Tahoma";
+      *css_font_variant = "small-caps";
+      break;
+    case ClosedCaptionStyle_Default:
+      *css_font_family = std::string();
+      break;
+  }
+}
+
+// Translates a Windows::Media::ClosedCaptioning::ClosedCaptionEdgeEffect to a
+// CSS style value.
+std::string GetEdgeEffectString(ClosedCaptionEdgeEffect edge_effect) {
+  switch (edge_effect) {
+    case ClosedCaptionEdgeEffect_None:
+      return "none";
+    case ClosedCaptionEdgeEffect_Raised:
+      return "-1px 0px 0px silver, 0px -1px 0px silver, 1px 1px 0px black, 2px "
+             "2px 0px black, 3px 3px 0px black";
+    case ClosedCaptionEdgeEffect_Depressed:
+      return "1px 1px 0px silver, 0px 1px 0px silver, -1px -1px 0px black, "
+             "-1px "
+             "0px 0px black";
+    case ClosedCaptionEdgeEffect_Uniform:
+      return "0px 0px 4px black, 0px 0px 4px black, 0px 0px 4px black, 0px 0px "
+             "4px black";
+    case ClosedCaptionEdgeEffect_DropShadow:
+      return "3px 3px 3px 2px black";
+    case ClosedCaptionEdgeEffect_Default:
+      return std::string();
+  }
+}
+
+// Translates a Windows::Media::ClosedCaptioning::ClosedCaptionSize to a CSS
+// style value.
+std::string GetCaptionSizeString(ClosedCaptionSize caption_size) {
+  switch (caption_size) {
+    case ClosedCaptionSize_FiftyPercent:
+      return "50%";
+    case ClosedCaptionSize_OneHundredPercent:
+      return "100%";
+    case ClosedCaptionSize_OneHundredFiftyPercent:
+      return "150%";
+    case ClosedCaptionSize_TwoHundredPercent:
+      return "200%";
+    case ClosedCaptionSize_Default:
+      return std::string();
+  }
+}
+
+// Translates a Windows::Media::ClosedCaptioning::ClosedCaptionColor to a CSS
+// color string.
+std::string GetCssColor(ClosedCaptionColor caption_color) {
+  switch (caption_color) {
+    case ClosedCaptionColor_Black:
+      return "black";
+    case ClosedCaptionColor_Red:
+      return "red";
+    case ClosedCaptionColor_Green:
+      return "green";
+    case ClosedCaptionColor_Blue:
+      return "blue";
+    case ClosedCaptionColor_Yellow:
+      return "yellow";
+    case ClosedCaptionColor_Magenta:
+      return "magenta";
+    case ClosedCaptionColor_Cyan:
+      return "cyan";
+    case ClosedCaptionColor_White:
+    case ClosedCaptionColor_Default:
+      return "white";
+  }
+}
+
+CaptionStyle InitializeFromSystemSettings() {
+  DCHECK_GE(base::win::GetVersion(), base::win::VERSION_WIN10);
+  DCHECK(base::FeatureList::IsEnabled(features::kSystemCaptionStyle));
+
+  // Need to do this check before using ScopedHString.
+  bool can_use_scoped_hstring =
+      base::win::ResolveCoreWinRTDelayload() &&
+      base::win::ScopedHString::ResolveCoreWinRTStringDelayload();
+
+  if (!can_use_scoped_hstring) {
+    DLOG(ERROR) << "Failed loading functions from combase.dll";
+    LogCapStyleWinError(__LINE__, E_FAIL);
+    return CaptionStyle();
+  }
+
+  base::win::ScopedHString closed_caption_properties_string =
+      base::win::ScopedHString::Create(
+          RuntimeClass_Windows_Media_ClosedCaptioning_ClosedCaptionProperties);
+  Microsoft::WRL::ComPtr<IClosedCaptionPropertiesStatics>
+      closed_caption_properties_statics;
+  HRESULT hr = base::win::RoGetActivationFactory(
+      closed_caption_properties_string.get(),
+      IID_PPV_ARGS(&closed_caption_properties_statics));
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to Get ActivationFactory for ClosedCaptionProperties"
+                << ", HRESULT: 0x" << std::hex << hr;
+    LogCapStyleWinError(__LINE__, hr);
+    return CaptionStyle();
+  }
+
+  ClosedCaptionSize font_size = ClosedCaptionSize_Default;
+  hr = closed_caption_properties_statics->get_FontSize(&font_size);
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to retrieve Font Size"
+                << ", HRESULT: 0x" << std::hex << hr;
+    LogCapStyleWinError(__LINE__, hr);
+    return CaptionStyle();
+  }
+
+  ClosedCaptionEdgeEffect edge_effect = ClosedCaptionEdgeEffect_Default;
+  hr = closed_caption_properties_statics->get_FontEffect(&edge_effect);
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to retrieve Font Effect"
+                << ", HRESULT: 0x" << std::hex << hr;
+    LogCapStyleWinError(__LINE__, hr);
+    return CaptionStyle();
+  }
+
+  ClosedCaptionStyle font_family = ClosedCaptionStyle_Default;
+  hr = closed_caption_properties_statics->get_FontStyle(&font_family);
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to retrieve Font Family"
+                << ", HRESULT: 0x" << std::hex << hr;
+    LogCapStyleWinError(__LINE__, hr);
+    return CaptionStyle();
+  }
+
+  ClosedCaptionColor font_color = ClosedCaptionColor_Default;
+  hr = closed_caption_properties_statics->get_FontColor(&font_color);
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to retrieve Font Color"
+                << ", HRESULT: 0x" << std::hex << hr;
+    LogCapStyleWinError(__LINE__, hr);
+    return CaptionStyle();
+  }
+
+  ClosedCaptionColor background_color = ClosedCaptionColor_Default;
+  hr =
+      closed_caption_properties_statics->get_BackgroundColor(&background_color);
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to retrieve Background Color"
+                << ", HRESULT: 0x" << std::hex << hr;
+    LogCapStyleWinError(__LINE__, hr);
+    return CaptionStyle();
+  }
+
+  CaptionStyle caption_style;
+  GetFontFamilyString(font_family, &(caption_style.font_family),
+                      &(caption_style.font_variant));
+  caption_style.text_size = GetCaptionSizeString(font_size);
+  caption_style.text_shadow = GetEdgeEffectString(edge_effect);
+  caption_style.text_color = GetCssColor(font_color);
+  caption_style.background_color = GetCssColor(background_color);
+
+  return caption_style;
+}
+
+}  // namespace
+
+CaptionStyle CaptionStyle::FromSystemSettings() {
+  CaptionStyle style;
+  if (base::win::GetVersion() >= base::win::VERSION_WIN10 &&
+      base::FeatureList::IsEnabled(features::kSystemCaptionStyle)) {
+    style = InitializeFromSystemSettings();
+  }
+  // Return default CaptionStyle for pre Win10 versions since system settings
+  // don't allow caption styling.
+  return style;
+}
+
+}  // namespace ui

ui/native_theme/caption_style_win_unittest.cc

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/native_theme/caption_style.h"
+
+#include "base/test/scoped_feature_list.h"
+#include "base/win/scoped_com_initializer.h"
+#include "base/win/windows_version.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/base/ui_base_features.h"
+
+namespace ui {
+
+// Test to ensure closed caption styling from system settings is used on
+// Windows 10.
+TEST(CaptionStyleWinTest, TestWinCaptionStyle) {
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndEnableFeature(features::kSystemCaptionStyle);
+
+  if (base::win::GetVersion() >= base::win::VERSION_WIN10) {
+    base::win::ScopedCOMInitializer com_initializer;
+    ASSERT_TRUE(com_initializer.Succeeded());
+
+    ui::CaptionStyle caption_style = ui::CaptionStyle::FromSystemSettings();
+    // Other caption style properties can be empty and shouldn't be checked.
+    EXPECT_TRUE(!caption_style.background_color.empty());
+    EXPECT_TRUE(!caption_style.text_color.empty());
+    EXPECT_TRUE(!caption_style.font_variant.empty());
+  }
+}
+
+}  // namespace ui

ui/native_theme/native_theme.cc

@@ -55,11 +55,14 @@ bool NativeTheme::SystemDarkModeEnabled() const {
 }
 
 CaptionStyle NativeTheme::GetSystemCaptionStyle() const {
-  std::string style =
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          ::switches::kForceCaptionStyle)) {
+    return CaptionStyle::FromSpec(
         base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-          switches::kForceCaptionStyle);
+            switches::kForceCaptionStyle));
+  }
 
-  return CaptionStyle::FromSpec(style);
+  return CaptionStyle::FromSystemSettings();
 }
 
 }  // namespace ui