How to attach a CSV file with the Google Chart API? I have created a Google Chart based View and it is working nicely.
How to give the facility as the user should be able to upload a CSV file and the data comes accordingly?
To my knowledge there is no way using Google Chart API to "* to upload a csv file and the data comes accordingly*" (as in your question).

However, you may want to have a look at the Easychart module as a possible alternative (which already has an official release for both Drupal 7 and Drupal 8).

It is a graphical user interface, using the Highcharts javascript library as its charting engine (which may require a commercial license though). It claims to support every Highcharts chart-type and option.

Some more details about this module:


It defines a new content type (= Chart) used to add charts to your site.
It creates a chart widget that can be used in your own content types.
It integrates with the WYSIWYG module and provides an editor button to add charts to your WYSIWYG content (CKeditor and TinyMCE are supported).
It provides an intuitive interface to configure charts through the Easychart plugin.
It supports pasting of CSV data to create charts from it.
overheid.vlaanderen.be contains some real world examples of a Drupal website with some charts created with Easycharts (ignore the text on that page if you're not familiar with this language, just concentrate on the charts).


Especially the bullet about "It supports pasting of CSV data to create charts from it." seems close to what you're looking for.

Resources:


Module documentation.
Video demonstration.