port fix from rubycdp#545

Author: crahles

lib/ferrum/client.rb

@@ -61,6 +61,7 @@ def event_name(event)
 
   class Client
     extend Forwardable
+
     delegate %i[timeout timeout=] => :options
 
     attr_reader :ws_url, :options, :subscriber
@@ -165,7 +166,7 @@ def raise_browser_error(error)
            "Inspected target navigated or closed"
         raise NodeNotFoundError, error
       # Context is lost, page is reloading
-      when "Cannot find context with specified id"
+      when "Cannot find context with specified id", /Failed to find context with id/
         raise NoExecutionContextError, error
       when "No target with given id found"
         raise NoSuchPageError

lib/ferrum/contexts.rb

@@ -5,6 +5,7 @@
 module Ferrum
   class Contexts
     ALLOWED_TARGET_TYPES = %w[page iframe].freeze
+    ABOUT_BLANK = "about:blank"
 
     include Enumerable
 
@@ -46,11 +47,18 @@ def create(**options)
       context
     end
 
-    def dispose(context_id)
+    def dispose(context_id) # rubocop:disable Naming/PredicateMethod
       context = @contexts[context_id]
       context.close_targets_connection
-      @client.command("Target.disposeBrowserContext", browserContextId: context.id)
-      @contexts.delete(context_id)
+
+      begin
+        @client.command("Target.disposeBrowserContext", browserContextId: context.id)
+      rescue NoExecutionContextError
+        warn "Browser context #{context.id} was already disposed" unless context.page&.url == ABOUT_BLANK
+      ensure
+        @contexts.delete(context_id)
+      end
+
       true
     end