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 appConstants.APP_WINDOW_COMPUTED_STYLES:
+      state = windowState.updateComputedStyles(state, action)
+      break
   }
   return state
 }

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

@@ -3,11 +3,47 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 const Immutable = require('immutable')
+const computedStyles = require('../constants/computedStyles')
+const windowState = require('../state/windowState')
+const appActions = require('../../../js/actions/appActions')
+const {getCurrentWindowId} = require('../../renderer/currentWindow')
 
-module.exports.getPinnedSiteProps = site => {
+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 getComputedProperty = (state, property) => {
+  const currentWindowIndex = windowState.getWindowIndexByWindowId(state, getCurrentWindowId())
+
+  return state.getIn(['windows', currentWindowIndex, 'computedStyles', property])
+}
+
+const updateComputedStyles = () => {
+  const root = window.getComputedStyle(document.querySelector(':root'))
+  const computedValues = getComputedStyleData(root)
+  appActions.updateComputedStyles(getCurrentWindowId(), computedValues)
+}
+
+module.exports = {
+  getPinnedSiteProps,
+  getComputedStyleData,
+  getComputedProperty,
+  updateComputedStyles
+}

app/common/state/windowState.js

@@ -146,6 +146,13 @@ const api = {
     return state.set('windows', windows.delete(index).insert(index, windowValue))
   },
 
+  updateComputedStyles: (state, action) => {
+    const windowIndex = api.getWindowIndexByWindowId(state, action.get('windowId'))
+    return state.mergeDeepIn(['windows', windowIndex], {
+      computedStyles: action.get('values')
+    })
+  },
+
   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

@@ -48,6 +48,7 @@ const {isFocused} = require('../../currentWindow')
 const debounce = require('../../../../js/lib/debounce')
 const locale = require('../../../../js/l10n')
 const imageUtil = require('../../../../js/lib/imageUtil')
+const windowsUtil = require('../../../common/lib/windowsUtil')
 
 // Constants
 const settings = require('../../../../js/constants/settings')
@@ -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(windowsUtil.getComputedProperty(state, '--download-bar-padding'), 10)
 
     return Object.assign({}, ownProps, props)
   }

app/renderer/components/window.js

@@ -21,8 +21,10 @@ const appActions = require('../../../js/actions/appActions')
 
 // Utils
 const cx = require('../../../js/lib/classSet')
+const windowsUtils = require('../../common/lib/windowsUtil')
 const {getPlatformStyles} = require('../../common/lib/platformUtil')
 const {getCurrentWindowId} = require('../currentWindow')
+const throttle = require('../../../js/lib/throttle')
 
 window.appActions = appActions
 
@@ -45,6 +47,7 @@ class Window extends React.Component {
 
     this.onChange = this.onChange.bind(this)
     this.onAppStateChange = this.onAppStateChange.bind(this)
+    this.updateComputedStyles = throttle(this.updateComputedStyles.bind(this), 66)
     windowStore.addChangeListener(this.onChange)
     appStoreRenderer.addChangeListener(this.onAppStateChange)
   }
@@ -93,11 +96,14 @@ class Window extends React.Component {
 
   componentDidMount () {
     appActions.windowReady(getCurrentWindowId())
+    this.updateComputedStyles()
+    window.addEventListener('resize', this.updateComputedStyles)
   }
 
   componentWillUnmount () {
     windowStore.removeChangeListener(this.onChange)
     appStoreRenderer.removeChangeListener(this.onAppStateChange)
+    window.removeEventListener('resize', this.updateComputedStyles)
   }
 
   shouldComponentUpdate (nextProps, nextState) {
@@ -127,6 +133,10 @@ class Window extends React.Component {
       })
     })
   }
+
+  updateComputedStyles () {
+    windowsUtils.updateComputedStyles()
+  }
 }
 
 Window.propTypes = { appState: PropTypes.object, frames: PropTypes.array, initWindowState: PropTypes.object }

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

@@ -1428,6 +1428,14 @@ const appActions = {
     dispatch({
       actionType: appConstants.APP_UPDATE_LOG_OPENED
     })
+  },
+
+  updateComputedStyles: function (windowId, values) {
+    dispatch({
+      actionType: appConstants.APP_WINDOW_COMPUTED_STYLES,
+      windowId,
+      values
+    })
   }
 
 }

js/constants/appConstants.js

@@ -132,7 +132,8 @@ const appConstants = {
   APP_REMOVE_PASSWORD_SITE: _, /** @param {Object} passwordDetail */
   APP_CLEAR_PASSWORDS: _,
   APP_UPDATE_LOG_OPENED: _,
-  APP_URL_BAR_SELECTED_INDEX_CHANGED: _
+  APP_URL_BAR_SELECTED_INDEX_CHANGED: _,
+  APP_WINDOW_COMPUTED_STYLES: _
 }
 
 module.exports = mapValuesByKeys(appConstants)