[webui][ntp] Show theme background image if set

This includes showing attributions and applying styles changes such as
text shadows.

Bug: 1032328
Change-Id: If28b2d98887baa802ae88bde68746100fabe2b44
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2090729
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Alex Gough <ajgo@chromium.org>
Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748833}

chrome/browser/resources/new_tab_page/app.html

 <style include="cr-shared-style">
+  :host {
+    --ntp-theme-shortcut-background-color: rgb(229, 231, 232);
+    --ntp-theme-text-color: var(--google-grey-800);
+    --ntp-theme-text-shadow: none;
+  }
+
+  @media (prefers-color-scheme: dark) {
+    :host {
+      --ntp-theme-shortcut-background-color: var(--google-grey-refresh-100);
+      --ntp-theme-text-color: white;
+    }
+  }
+
+  :host([show-background-image_]) {
+    --ntp-theme-text-shadow: 0 0 16px rgba(0, 0, 0, .3);
+  }
+
   #background {
+    height: 100%;
+    position: relative;
+    width: 100%;
+  }
+
+  #background > * {
+    height: 100%;
+    position: absolute;
+    top: 0;
+    width: 100%;
+  }
+
+  #backgroundImage {
+    border: none;
+  }
+
+  #backgroundGradient {
+    background: linear-gradient(rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.3));
+  }
+
+  #content {
     align-items: center;
     display: flex;
     flex-direction: column;
-    height: 100%;
-    width: 100%;
   }
 
   #voiceSearchButton {
@@ -31,37 +67,92 @@
     width: 100%;
   }
 
+  #customizeButtonContainer {
+    background-color: var(--ntp-background-override-color);
+    border-radius: calc(0.5 * var(--cr-button-height));
+    bottom: 16px;
+    position: absolute;
+  }
+
+  :host-context([dir='ltr']) #customizeButtonContainer {
+    right: 16px;
+  }
+
+  :host-context([dir='rtl']) #customizeButtonContainer {
+    left: 16px;
+  }
+
   #customizeButton {
     border: none;
     border-radius: calc(0.5 * var(--cr-button-height));
-    bottom: 16px;
     box-shadow: 0 3px 6px rgba(0, 0, 0, 0.16), 0 1px 2px rgba(0, 0, 0, 0.23);
     font-weight: 400;
+  }
+
+  #customizeIcon {
+    -webkit-mask-image: url(icons/icon_pencil.svg);
+    -webkit-mask-repeat: no-repeat;
+    -webkit-mask-size: 100%;
+    background-color: var(--text-color);
+    height: 16px;
+    margin-inline-end: 8px;
+    width: 16px;
+  }
+
+  #backgroundImageAttribution {
+    border-radius: 8px;
+    bottom: 16px;
+    color: var(--ntp-theme-text-color);
+    line-height: 20px;
+    max-width: 50vw;
+    padding: 8px;
     position: absolute;
+    text-shadow: var(--ntp-theme-text-shadow);
   }
 
-  #customizeButton:not(:hover) {
-    background-color: var(--ntp-background-override-color);
+  :host-context([dir='ltr']) #backgroundImageAttribution {
+    left: 16px;
   }
 
-  :host-context([dir='ltr']) #customizeButton {
+  :host-context([dir='rtl']) #backgroundImageAttribution {
     right: 16px;
   }
 
-  :host-context([dir='rtl']) #customizeButton {
-    left: 16px;
+  #backgroundImageAttribution:hover {
+    background: rgba(var(--google-grey-900-rgb), .1);
   }
 
-  #customizeIcon {
-    -webkit-mask-image: url(icons/icon_pencil.svg);
+  #backgroundImageAttribution1Container {
+    align-items: center;
+    display: flex;
+    flex-direction: row;
+  }
+
+  #linkIcon {
+    -webkit-mask-image: url(icons/link.svg);
     -webkit-mask-repeat: no-repeat;
     -webkit-mask-size: 100%;
-    background-color: var(--text-color);
+    background-color: var(--ntp-theme-text-color);
     height: 16px;
     margin-inline-end: 8px;
     width: 16px;
   }
 
+  #backgroundImageAttribution1,
+  #backgroundImageAttribution2 {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+  }
+
+  #backgroundImageAttribution1 {
+    font-size: 0.875rem;
+  }
+
+  #backgroundImageAttribution2 {
+    font-size: 0.75rem;
+  }
+
   ntp-most-visited[dark] {
     --icon-button-color-active: var(--google-grey-refresh-300);
     --icon-button-color: white;
@@ -69,15 +160,19 @@
   }
 </style>
 <div id="background"
-    style="background-color: [[rgbOrInherit_(theme_.backgroundColor)]];">
+    style="background-color: [[rgbOrInherit_(theme_.backgroundColor)]];
+        --ntp-theme-text-color: [[rgbOrInherit_(theme_.shortcutTextColor)]];
+        --ntp-theme-shortcut-background-color:
+              [[rgbOrInherit_(theme_.shortcutBackgroundColor)]];">
+  <ntp-untrusted-iframe id="backgroundImage" path="[[backgroundImagePath_]]"
+      hidden="[[!showBackgroundImage_]]">
+  </ntp-untrusted-iframe>
+  <div id="backgroundGradient" hidden="[[!showBackgroundImage_]]"></div>
+  <div id="content">
     <button id="voiceSearchButton" on-click="onVoiceSearchClick_"
         title="$i18n{voiceSearchButtonLabel}">
     </button>
-  <ntp-most-visited id="mostVisited" dark$="[[theme_.isDark]]"
-      style="--icon-background-color:
-            [[rgbOrInherit_(theme_.shortcutBackgroundColor)]];
-          --tile-title-color:
-            [[rgbOrInherit_(theme_.shortcutTextColor)]];">
+    <ntp-most-visited id="mostVisited" dark$="[[theme_.isDark]]">
     </ntp-most-visited>
     <dom-if if="[[showCustomizeDialog_]]" restamp>
       <template>
@@ -94,8 +189,28 @@
     </dom-if>
     <ntp-untrusted-iframe id="promo" path="promo" hidden$="[[!promoLoaded_]]">
     </ntp-untrusted-iframe>
+    <!-- cr-button is transparent on hover. This leads to incorrect results when
+         a custom background is set. Therefore, wrap customize button in
+         container to enfore solid background color. -->
+    <div id="customizeButtonContainer">
       <cr-button id="customizeButton" on-click="onCustomizeClick_">
         <div id="customizeIcon"></div>
         $i18n{customizeButton}
       </cr-button>
+    </div>
+    <a id="backgroundImageAttribution"
+        href="[[theme_.backgroundImageAttributionUrl.url]]"
+        hidden="[[!theme_.backgroundImageAttribution1]]">
+      <div id="backgroundImageAttribution1Container">
+        <div id="linkIcon"></div>
+        <div id="backgroundImageAttribution1">
+          [[theme_.backgroundImageAttribution1]]
+        </div>
+      </div>
+      <div id="backgroundImageAttribution2"
+          hidden="[[!theme_.backgroundImageAttribution2]]">
+        [[theme_.backgroundImageAttribution2]]
+      </div>
+    </a>
+  </div>
 </div>

chrome/browser/resources/new_tab_page/app.js

@@ -42,6 +42,19 @@ class AppElement extends PolymerElement {
 
       /** @private */
       showVoiceSearchOverlay_: Boolean,
+
+      /** @private */
+      showBackgroundImage_: {
+        computed: 'computeShowBackgroundImage_(theme_)',
+        reflectToAttribute: true,
+        type: Boolean,
+      },
+
+      /** @private */
+      backgroundImagePath_: {
+        computed: 'computeBackgroundImagePath_(theme_)',
+        type: String,
+      },
     };
   }
 
@@ -112,6 +125,25 @@ class AppElement extends PolymerElement {
   rgbOrInherit_(skColor) {
     return skColor ? skColorToRgb(skColor) : 'inherit';
   }
+
+  /**
+   * @return {boolean}
+   * @private
+   */
+  computeShowBackgroundImage_() {
+    return !!this.theme_ && !!this.theme_.backgroundImageUrl;
+  }
+
+  /**
+   * @return {string}
+   * @private
+   */
+  computeBackgroundImagePath_() {
+    if (!this.theme_ || !this.theme_.backgroundImageUrl) {
+      return '';
+    }
+    return `image?${this.theme_.backgroundImageUrl.url}`;
+  }
 }
 
 customElements.define(AppElement.is, AppElement);

chrome/browser/resources/new_tab_page/most_visited.html

@@ -3,11 +3,9 @@
     --icon-size: 48px;
     --tile-size: 112px;
     --tile-margin: 16px;
-    --icon-background-color: rgb(229, 231, 232);
     --icon-button-color: var(--google-grey-600);
     --icon-button-color-active: var(--google-grey-refresh-700);
     --tile-hover-color: rgba(var(--google-grey-900-rgb), .1);
-    --tile-title-color: var(--google-grey-800);
   }
 
   #container {
@@ -28,7 +26,7 @@
     -webkit-mask-image: url(chrome://resources/images/add.svg);
     -webkit-mask-repeat: no-repeat;
     -webkit-mask-size: 100%;
-    background-color: var(--tile-title-color);
+    background-color: var(--ntp-theme-text-color);
     height: 24px;
     width: 24px;
   }
@@ -68,7 +66,7 @@
 
   .tile-icon {
     align-items: center;
-    background-color: var(--icon-background-color);
+    background-color: var(--ntp-theme-shortcut-background-color);
     border-radius: 50%;
     display: flex;
     height: var(--icon-size);
@@ -82,11 +80,12 @@
   }
 
   .tile-title {
-    color: var(--tile-title-color);
+    color: var(--ntp-theme-text-color);
     margin-top:  16px;
     overflow: hidden;
     text-align: center;
     text-overflow: ellipsis;
+    text-shadow: var(--ntp-theme-text-shadow);
     white-space: nowrap;
     width: 88px;
   }
@@ -138,11 +137,9 @@
 
   @media (prefers-color-scheme: dark) {
     :host {
-      --icon-background-color: var(--google-grey-refresh-100);
       --icon-button-color: var(--google-grey-400);
       --icon-button-color-active: var(--google-grey-200);
       --tile-hover-color: rgba(255, 255, 255, .1);
-      --tile-title-color: white;
     }
   }
 </style>

chrome/browser/resources/new_tab_page/new_tab_page_resources.grd

@@ -74,6 +74,8 @@
           file="icons/googlemic_clr_24px.svg" type="BINDATA" compress="gzip" />
       <include name="IDR_NEW_TAB_PAGE_MIC_SVG"
           file="icons/mic.svg" type="BINDATA" compress="gzip" />
+      <include name="IDR_NEW_TAB_PAGE_LINK_SVG"
+          file="icons/link.svg" type="BINDATA" compress="gzip" />
       <include name="IDR_NEW_TAB_PAGE_MINI_PAGE_JS"
           file="${root_gen_dir}/chrome/browser/resources/new_tab_page/mini_page.js"
           use_base_dir="false" type="BINDATA" compress="gzip" />

chrome/browser/ui/webui/new_tab_page/new_tab_page.mojom

@@ -88,6 +88,14 @@ struct Theme {
   skia.mojom.SkColor shortcut_text_color;
   // True if the theme is dark (e.g. NTP background color is dark).
   bool is_dark;
+  // URL to the background image. Can point to untrusted content.
+  url.mojom.Url? background_image_url;
+  // Human readable attributions of the background image.
+  string? background_image_attribution_1;
+  string? background_image_attribution_2;
+  // URL associated with the background image. Used for href.
+  url.mojom.Url? background_image_attribution_url;
+
   // TODO(crbug.com/1040682): Additional info about the theme depending on the
   // type. That should be optional since only some themes require it. However,
   // making this field optional crashes JS.

chrome/browser/ui/webui/new_tab_page/new_tab_page_handler.cc

@@ -54,6 +54,21 @@ new_tab_page::mojom::ThemePtr MakeTheme(const NtpTheme& ntp_theme) {
   theme->shortcut_background_color = ntp_theme.shortcut_color;
   theme->shortcut_text_color = ntp_theme.text_color;
   theme->is_dark = !color_utils::IsDark(ntp_theme.text_color);
+  if (!ntp_theme.custom_background_url.is_empty()) {
+    theme->background_image_url = ntp_theme.custom_background_url;
+  }
+  if (!ntp_theme.custom_background_attribution_line_1.empty()) {
+    theme->background_image_attribution_1 =
+        ntp_theme.custom_background_attribution_line_1;
+  }
+  if (!ntp_theme.custom_background_attribution_line_2.empty()) {
+    theme->background_image_attribution_2 =
+        ntp_theme.custom_background_attribution_line_2;
+  }
+  if (!ntp_theme.custom_background_attribution_action_url.is_empty()) {
+    theme->background_image_attribution_url =
+        ntp_theme.custom_background_attribution_action_url;
+  }
   return theme;
 }
 
@@ -78,7 +93,7 @@ NewTabPageHandler::NewTabPageHandler(
   CHECK(web_contents_);
   instant_service_->AddObserver(this);
   ntp_background_service_->AddObserver(this);
-  page_->SetTheme(MakeTheme(*instant_service_->GetInitializedNtpTheme()));
+  instant_service_->UpdateNtpTheme();
 }
 
 NewTabPageHandler::~NewTabPageHandler() {

chrome/test/data/webui/new_tab_page/app_test.js

@@ -5,7 +5,7 @@
 import 'chrome://new-tab-page/app.js';
 
 import {BrowserProxy} from 'chrome://new-tab-page/browser_proxy.js';
-import {assertStyle, createTestProxy} from 'chrome://test/new_tab_page/test_support.js';
+import {assertNotStyle, assertStyle, createTestProxy} from 'chrome://test/new_tab_page/test_support.js';
 import {flushTasks} from 'chrome://test/test_util.m.js';
 
 suite('NewTabPageAppTest', () => {
@@ -58,6 +58,10 @@ suite('NewTabPageAppTest', () => {
       shortcutBackgroundColor: {value: 0xff00ff00},
       shortcutTextColor: {value: 0xff0000ff},
       isDark: false,
+      backgroundImageUrl: null,
+      backgroundImageAttribution1: '',
+      backgroundImageAttribution2: '',
+      backgroundImageAttributionUrl: null,
     };
 
     // Act.
@@ -69,7 +73,7 @@ suite('NewTabPageAppTest', () => {
         theme, app.shadowRoot.querySelector('ntp-customize-dialog').theme);
   });
 
-  test('setting theme updates background color and most visited', async () => {
+  test('setting theme updates ntp', async () => {
     // Act.
     testProxy.callbackRouterRemote.setTheme({
       type: newTabPage.mojom.ThemeType.DEFAULT,
@@ -84,11 +88,14 @@ suite('NewTabPageAppTest', () => {
     // Assert.
     assertStyle(app.$.background, 'background-color', 'rgb(255, 0, 0)');
     assertStyle(
-        app.shadowRoot.querySelector('ntp-most-visited'),
-        '--icon-background-color', 'rgb(0, 255, 0)');
-    assertStyle(
-        app.shadowRoot.querySelector('ntp-most-visited'), '--tile-title-color',
-        'rgb(0, 0, 255)');
+        app.$.background, '--ntp-theme-shortcut-background-color',
+        'rgb(0, 255, 0)');
+    assertStyle(app.$.background, '--ntp-theme-text-color', 'rgb(0, 0, 255)');
+    assertFalse(app.$.background.hasAttribute('has-background-image'));
+    assertStyle(app.$.backgroundImage, 'display', 'none');
+    assertStyle(app.$.backgroundGradient, 'display', 'none');
+    assertStyle(app.$.backgroundImageAttribution, 'display', 'none');
+    assertStyle(app.$.backgroundImageAttribution2, 'display', 'none');
   });
 
   test('clicking voice search button opens voice search overlay', async () => {
@@ -99,4 +106,59 @@ suite('NewTabPageAppTest', () => {
     // Assert.
     assertTrue(!!app.shadowRoot.querySelector('ntp-voice-search-overlay'));
   });
+
+  test('setting background images shows iframe and gradient', async () => {
+    // Act.
+    const theme = {
+      type: newTabPage.mojom.ThemeType.DEFAULT,
+      info: {chromeThemeId: 0},
+      backgroundColor: {value: 0xffff0000},
+      shortcutBackgroundColor: {value: 0xff00ff00},
+      shortcutTextColor: {value: 0xff0000ff},
+      isDark: false,
+      backgroundImageUrl: {url: 'https://img.png'},
+      backgroundImageAttribution1: '',
+      backgroundImageAttribution2: '',
+      backgroundImageAttributionUrl: null,
+    };
+
+    // Act.
+    testProxy.callbackRouterRemote.setTheme(theme);
+    await testProxy.callbackRouterRemote.$.flushForTesting();
+
+    // Assert.
+    assertNotStyle(app.$.backgroundImage, 'display', 'none');
+    assertNotStyle(app.$.backgroundGradient, 'display', 'none');
+    assertNotStyle(app.$.backgroundImageAttribution, 'text-shadow', 'none');
+    assertEquals(app.$.backgroundImage.path, 'image?https://img.png');
+  });
+
+  test('setting attributions shows attributions', async function() {
+    // Act.
+    const theme = {
+      type: newTabPage.mojom.ThemeType.DEFAULT,
+      info: {chromeThemeId: 0},
+      backgroundColor: {value: 0xffff0000},
+      shortcutBackgroundColor: {value: 0xff00ff00},
+      shortcutTextColor: {value: 0xff0000ff},
+      isDark: false,
+      backgroundImageUrl: null,
+      backgroundImageAttribution1: 'foo',
+      backgroundImageAttribution2: 'bar',
+      backgroundImageAttributionUrl: {url: 'https://info.com'},
+    };
+
+    // Act.
+    testProxy.callbackRouterRemote.setTheme(theme);
+    await testProxy.callbackRouterRemote.$.flushForTesting();
+
+    // Assert.
+    assertNotStyle(app.$.backgroundImageAttribution, 'display', 'none');
+    assertNotStyle(app.$.backgroundImageAttribution2, 'display', 'none');
+    assertEquals(
+        app.$.backgroundImageAttribution.getAttribute('href'),
+        'https://info.com');
+    assertEquals(app.$.backgroundImageAttribution1.textContent.trim(), 'foo');
+    assertEquals(app.$.backgroundImageAttribution2.textContent.trim(), 'bar');
+  });
 });

chrome/test/data/webui/new_tab_page/most_visited_test.js

@@ -613,8 +613,9 @@ suite('NewTabPageMostVisitedTest', () => {
 
   test('setting color styles tile color', () => {
     // Act.
-    mostVisited.style.setProperty('--tile-title-color', 'blue');
-    mostVisited.style.setProperty('--icon-background-color', 'red');
+    mostVisited.style.setProperty('--ntp-theme-text-color', 'blue');
+    mostVisited.style.setProperty(
+        '--ntp-theme-shortcut-background-color', 'red');
 
     // Assert.
     queryAll('.tile-title').forEach(tile => {