Remove browser error reporting

No one look at it. It also contains browser extension errors and the
included error message isn't useful either.

app/controllers/user_controller.rb

@@ -363,17 +363,6 @@ def set_avatar
     @post = Post.find(params[:id])
   end
 
-  def error
-    report = params[:report]
-
-    file = "#{Rails.root}/log/user_errors.log"
-    File.open(file, "a") do |f|
-      f.write(report.to_s + "\n\n\n-------------------------------------------\n\n\n")
-    end
-
-    render json: { success: true }
-  end
-
   private
 
   def get_view_name_for_edit(param)

app/javascript/src/classes/tag_completion.coffee

@@ -422,8 +422,7 @@ export default class TagCompletion
     results.each (tag) ->
       m = tag.match(/(\d+)`([^`]*)`(([^ ]*)`)? /)
       if !m
-        ReportError 'Unparsable cached tag: \'' + tag + '\'', null, null, null, null
-        throw 'Unparsable cached tag: \'' + tag + '\''
+        throw "Unparsable cached tag: '#{tag}'"
       tag = m[2]
       tag_type = Post.tag_type_names[m[1]]
       aliases = m[4]

app/javascript/src/legacy/common.coffee

@@ -89,10 +89,6 @@ window.InitAdvancedEditing = ->
   $(document.documentElement).removeClassName 'hide-advanced-editing'
   return
 
-window.onerror = (error, file, line) ->
-  ReportError error, file, line, null
-  return
-
 ### Return the squared distance between two points. ###
 window.distance_squared = (x1, y1, x2, y2) ->
   (x1 - x2) ** 2 + (y1 - y2) ** 2
@@ -539,82 +535,3 @@ window.TrackFocus = ->
     return
   ).bindAsEventListener(this)
   return
-
-window.FormatError = (message, file, line, exc, info) ->
-  report = ''
-  report += 'Error: ' + message + '\n'
-  if info?
-    report += info
-  report += 'UA: ' + window.navigator.userAgent + '\n'
-  report += 'URL: ' + window.location.href + '\n'
-  cookies = document.cookie
-  cookies = cookies.replace(/(pass_hash)=[0-9a-f]{40}/, '$1=(removed)')
-  try
-    report += 'Cookies: ' + decodeURIComponent(cookies) + '\n'
-  catch e
-    report += 'Cookies (couldn\'t decode): ' + cookies + '\n'
-  if 'localStorage' of window
-
-    ### FF's localStorage is broken; we can't iterate over it.  Name the keys we use explicitly. ###
-
-    keys = []
-    try
-      for storageKey of localStorage
-        keys.push storageKey
-    catch e
-      keys = [
-        'sample_urls'
-        'sample_url_fifo'
-        'tag_data'
-        'tag_data_version'
-        'recent_tags'
-        'tag_data_format'
-      ]
-    i = 0
-    while i < keys.length
-      key = keys[i]
-      try
-        if !(key of localStorage)
-          ++i
-          continue
-        data = localStorage[key]
-        length = data.length
-        if data.length > 512
-          data = data.slice(0, 512)
-        report += 'localStorage.' + key + ' (size: ' + length + '): ' + data + '\n'
-      catch e
-        report += '(ignored errors retrieving localStorage for ' + key + ': ' + e + ')\n'
-      ++i
-  if exc and exc.stack
-    report += '\n' + exc.stack + '\n'
-  if file
-    report += 'File: ' + file
-    if line?
-      report += ' line ' + line + '\n'
-  report
-
-window.reported_error = false
-
-window.ReportError = (message, file, line, exc, info) ->
-  if navigator.userAgent.match(/.*MSIE [67]/)
-    return
-
-  ### Only attempt to report an error once per page load. ###
-
-  if window.reported_error
-    return
-  window.reported_error = true
-
-  ### Only report an error at most once per hour. ###
-
-  if document.cookie.indexOf('reported_error=1') != -1
-    return
-  expiration = new Date
-  expiration.setTime expiration.getTime() + 60 * 60 * 1000
-  document.cookie = 'reported_error=1; path=/; expires=' + expiration.toGMTString()
-  report = FormatError((if exc then exc.message else message), file, line, exc, info)
-  try
-    jQuery.post '/user/error.json', report: report
-  catch e
-    alert 'Error: ' + e
-  return

config/routes.rb

@@ -230,7 +230,6 @@
   match "user/change_password", via: [ :post, :get ]
   post "user/check"
   match "user/edit", via: [ :post, :get ]
-  match "user/error", via: [ :post, :get ]
   match "user/home", via: [ :post, :get ]
   match "user/invites", via: [ :post, :get ]
   match "user/login", via: [ :post, :get ]