chromium/fuchsia/engine/browser/theme_manager.cc


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162

// Copyright 2020 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 "fuchsia/engine/browser/theme_manager.h"

#include "base/check.h"
#include "base/fuchsia/fuchsia_logging.h"
#include "third_party/blink/public/mojom/css/preferred_color_scheme.mojom.h"
#include "third_party/blink/public/mojom/webpreferences/web_preferences.mojom.h"

namespace {

using blink::mojom::PreferredColorScheme;
using fuchsia::settings::ThemeType;

constexpr PreferredColorScheme kFallbackColorScheme =
    PreferredColorScheme::kLight;

PreferredColorScheme ThemeTypeToBlinkScheme(ThemeType type) {
  switch (type) {
    case ThemeType::LIGHT:
      return PreferredColorScheme::kLight;
    case ThemeType::DARK:
      return PreferredColorScheme::kDark;
    case ThemeType::DEFAULT:
    case ThemeType::AUTO:
      NOTREACHED();
      return kFallbackColorScheme;
  }
}

}  // namespace

ThemeManager::ThemeManager(content::WebContents* web_contents)
    : web_contents_(web_contents) {
  DCHECK(web_contents_);

  // Per the FIDL API, the default theme is LIGHT.
  SetTheme(ThemeType::LIGHT, base::DoNothing());
}

ThemeManager::~ThemeManager() = default;

void ThemeManager::SetTheme(
    ThemeType theme,
    ThemeManager::OnSetThemeCompleteCallback on_set_complete) {
  requested_theme_ = theme;

  on_set_complete_ = std::move(on_set_complete);
  switch (*requested_theme_) {
    case ThemeType::AUTO:
      if (!EnsureDisplayService()) {
        OnDisplayServiceMissing();
        return;
      }
      break;
    case ThemeType::DEFAULT:
      std::move(on_set_complete_).Run(false);
      return;
    case ThemeType::LIGHT:
    case ThemeType::DARK:
      break;
  }

  ApplyTheme();
}

bool ThemeManager::EnsureDisplayService() {
  if (observed_display_service_error_)
    return false;

  if (display_service_)
    return true;

  display_service_ = base::ComponentContextForProcess()
                         ->svc()
                         ->Connect<fuchsia::settings::Display>();

  display_service_.set_error_handler([this](zx_status_t status) {
    ZX_LOG_IF(ERROR, status != ZX_ERR_PEER_CLOSED, status)
        << "fuchsia.settings.Display disconnected.";

    observed_display_service_error_ = true;

    // If the channel to the Display service was dropped before we received a
    // response from WatchForDisplayChanges, then it's likely that the service
    // isn't available in the namespace at all, which should be reported as
    // an error on the Frame.
    // Otherwise, if a failure was detected for a Display that was previously
    // functioning, it should be treated as a transient issue and the last known
    // system theme should be used.
    if (requested_theme_ && (*requested_theme_ == ThemeType::AUTO) &&
        !did_receive_first_watch_result_) {
      OnDisplayServiceMissing();
    }
  });

  WatchForDisplayChanges();
  return true;
}

void ThemeManager::OnDisplayServiceMissing() {
  LOG(ERROR) << "AUTO theme requires access to the "
                "`fuchsia.settings.Display` service to work.";

  if (on_set_complete_)
    std::move(on_set_complete_).Run(false);
}

void ThemeManager::ApplyTheme() {
  DCHECK(requested_theme_);

  blink::web_pref::WebPreferences web_preferences =
      web_contents_->GetOrCreateWebPreferences();

  if (requested_theme_ == ThemeType::AUTO) {
    if (!system_theme_) {
      // Defer theme application until we receive a system theme.
      return;
    }

    web_preferences.preferred_color_scheme =
        ThemeTypeToBlinkScheme(*system_theme_);
  } else {
    DCHECK(requested_theme_ == ThemeType::LIGHT ||
           requested_theme_ == ThemeType::DARK);

    web_preferences.preferred_color_scheme =
        ThemeTypeToBlinkScheme(*requested_theme_);
  }

  web_contents_->SetWebPreferences(web_preferences);

  if (on_set_complete_)
    std::move(on_set_complete_).Run(true);
}

void ThemeManager::WatchForDisplayChanges() {
  DCHECK(display_service_);

  // Will reply immediately for the first call of Watch(). Subsequent calls to
  // Watch() will be replied to as changes occur.
  display_service_->Watch(
      fit::bind_member(this, &ThemeManager::OnWatchResultReceived));
}

void ThemeManager::OnWatchResultReceived(
    fuchsia::settings::DisplaySettings settings) {
  did_receive_first_watch_result_ = true;

  if (settings.has_theme() && settings.theme().has_theme_type() &&
      (settings.theme().theme_type() == ThemeType::DARK ||
       settings.theme().theme_type() == ThemeType::LIGHT)) {
    system_theme_ = settings.theme().theme_type();
  } else {
    system_theme_ = base::nullopt;
  }

  ApplyTheme();
  WatchForDisplayChanges();
}