Saves computed styles in the state

Resolves brave#9149

Auditors:

Test Plan:

app/browser/reducers/windowsReducer.js

@@ -66,6 +66,9 @@ const windowsReducer = (state, action, immutableAction) => {
     case windowConstants.WINDOW_SHOULD_OPEN_DEV_TOOLS:
       windows.openDevTools(action.get('windowId'))
       break
+    case windowConstants.WINDOW_COMPUTED_STYLES_CHANGED:
+      state = windowState.setComputedStyles(state, action.get('windowId'), action.get('values'))
+      break
   }
   return state
 }

app/browser/windows.js

@@ -9,7 +9,7 @@ const debounce = require('../../js/lib/debounce')
 const {getSetting} = require('../../js/settings')
 const locale = require('../locale')
 const LocalShortcuts = require('../localShortcuts')
-const {getPinnedSiteProps} = require('../common/lib/windowsUtil')
+const {getPinnedSiteProps, updateComputedStyles} = require('../common/lib/windowsUtil')
 const {makeImmutable} = require('../common/state/immutableUtil')
 const {getPinnedTabsByWindowId} = require('../common/state/tabState')
 const messages = require('../../js/constants/messages')
@@ -58,6 +58,7 @@ const updateWindow = (windowId) => {
   let windowValue = getWindowValue(windowId)
   if (windowValue) {
     appActions.windowUpdated(windowValue)
+    updateComputedStyles()
   }
 }
 

app/common/constants/computedStyles.js

@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const computedStyles = {
+  'bookmark-item': [
+    'max-width',
+    'padding',
+    'margin',
+    'font-size'
+  ],
+  'bookmark-item-chevron': [
+    'margin'
+  ],
+  'bookmarks-toolbar': [
+    'padding'
+  ],
+  'default': [
+    'font-family'
+  ],
+  'download-bar': [
+    'buttons',
+    'height',
+    'padding'
+  ],
+  'download-item': [
+    'margin',
+    'width'
+  ],
+  'navbar': [
+    'height'
+  ]
+}
+
+module.exports = computedStyles

app/common/lib/windowsUtil.js

@@ -4,10 +4,44 @@
 
 const Immutable = require('immutable')
 
-module.exports.getPinnedSiteProps = site => {
+// Constants
+const computedStyles = require('../constants/computedStyles')
+
+// Actions
+const windowActions = require('../../../js/actions/windowActions')
+
+// Utils
+const {getCurrentWindowId} = require('../../renderer/currentWindow')
+
+const getPinnedSiteProps = site => {
   return Immutable.fromJS({
     location: site.get('location'),
     order: site.get('order'),
     partitionNumber: site.get('partitionNumber') || 0
   })
 }
+
+const getComputedStyleData = (root) => {
+  const result = {}
+
+  Object.keys(computedStyles).forEach(group => {
+    computedStyles[group].forEach(prop => {
+      const value = `--${group}-${prop}`
+      result[value] = root.getPropertyValue(value).trim()
+    })
+  })
+
+  return result
+}
+
+const updateComputedStyles = () => {
+  const root = window.getComputedStyle(document.querySelector(':root'))
+  const computedValues = getComputedStyleData(root)
+  windowActions.computedStylesChanged(getCurrentWindowId(), computedValues)
+}
+
+module.exports = {
+  getPinnedSiteProps,
+  getComputedStyleData,
+  updateComputedStyles
+}

app/common/state/windowState.js

@@ -146,6 +146,18 @@ const api = {
     return state.set('windows', windows.delete(index).insert(index, windowValue))
   },
 
+  setComputedStyles: (state, windowId, computedStyles) => {
+    const windowIndex = api.getWindowIndexByWindowId(state, windowId)
+    return state.mergeDeepIn(['windows', windowIndex], {
+      computedStyles: computedStyles
+    })
+  },
+
+  getComputedProperty: (state, property) => {
+    const currentWindowIndex = api.getWindowIndexByWindowId(state, api.getActiveWindowId(state))
+    return state.getIn(['windows', currentWindowIndex, 'computedStyles', property])
+  },
+
   getWindows: (state) => {
     state = validateState(state)
     return state.get('windows')

app/renderer/components/download/downloadsBar.js

@@ -20,6 +20,7 @@ const appActions = require('../../../../js/actions/appActions')
 // Utils
 const contextMenus = require('../../../../js/contextMenus')
 const downloadUtil = require('../../../../js/state/downloadUtil')
+const windowsUtils = require('../../../common/lib/windowsUtil')
 const cx = require('../../../../js/lib/classSet')
 
 class DownloadsBar extends React.Component {
@@ -34,6 +35,14 @@ class DownloadsBar extends React.Component {
     webviewActions.setWebviewFocused()
   }
 
+  componentDidMount () {
+    windowsUtils.updateComputedStyles()
+  }
+
+  componentWillUnmount () {
+    windowsUtils.updateComputedStyles()
+  }
+
   onShowDownloads () {
     appActions.createTabRequested({
       activateIfOpen: true,

app/renderer/components/frame/frame.js

@@ -26,6 +26,7 @@ const appStoreRenderer = require('../../../../js/stores/appStoreRenderer')
 const siteSettings = require('../../../../js/state/siteSettings')
 const siteSettingsState = require('../../../common/state/siteSettingsState')
 const tabState = require('../../../common/state/tabState')
+const windowState = require('../../../common/state/windowState')
 
 // Utils
 const frameStateUtil = require('../../../../js/state/frameStateUtil')
@@ -505,11 +506,7 @@ class Frame extends React.Component {
       e.stopPropagation()
     })
     this.webview.addEventListener('update-target-url', (e) => {
-      if (!this.root) {
-        this.root = window.getComputedStyle(document.querySelector(':root'))
-        this.downloadsBarHeight = Number.parseInt(this.root.getPropertyValue('--downloads-bar-height'), 10)
-      }
-      let nearBottom = e.y > (window.innerHeight - 150 - this.downloadsBarHeight)
+      let nearBottom = e.y > (window.innerHeight - 150 - this.props.downloadsBarHeight)
       let mouseOnLeft = e.x < (window.innerWidth / 2)
       let showOnRight = nearBottom && mouseOnLeft
       windowActions.setLinkHoverPreview(e.url, showOnRight)
@@ -955,6 +952,7 @@ class Frame extends React.Component {
     props.allSiteSettings = allSiteSettings // TODO (nejc) can be improved even more
     props.tabUrl = tab && tab.get('url')
     props.partitionNumber = frame.get('partitionNumber')
+    props.downloadsBarHeight = Number.parseInt(windowState.getComputedProperty(state, '--download-bar-padding'), 10)
 
     return Object.assign({}, ownProps, props)
   }

docs/state.md

@@ -356,6 +356,7 @@ AppStore
   },
   windows: [{
     // persistent properties
+    computedStyles: object, // all computed styles defined in computedStyles.js
     focused: boolean,
     height: number,
     left: number,

js/actions/appActions.js

@@ -1429,7 +1429,6 @@ const appActions = {
       actionType: appConstants.APP_UPDATE_LOG_OPENED
     })
   }
-
 }
 
 module.exports = appActions

js/actions/windowActions.js

@@ -1099,6 +1099,14 @@ const windowActions = {
       partition,
       tabId
     })
+  },
+
+  computedStylesChanged: function (windowId, values) {
+    dispatch({
+      actionType: windowConstants.WINDOW_COMPUTED_STYLES_CHANGED,
+      windowId,
+      values
+    })
   }
 }
 

js/constants/windowConstants.js

@@ -98,7 +98,8 @@ const windowConstants = {
   WINDOW_SHOULD_OPEN_DEV_TOOLS: _,
   WINDOW_SET_ALL_AUDIO_MUTED: _,
   WINDOW_ON_GO_BACK_LONG: _,
-  WINDOW_ON_GO_FORWARD_LONG: _
+  WINDOW_ON_GO_FORWARD_LONG: _,
+  WINDOW_COMPUTED_STYLES_CHANGED: _
 }
 
 module.exports = mapValuesByKeys(windowConstants)