In Chrome Canary 76.0.3804.0, PDF document in iframe tag forces tab title to change to the document name (wrong behavior).
On the other hand, document.title on JavaScript doesn't reflect this (correct behavior).
Default document.title of this page is "Chrome bug 13", and the title of this tab is also "Chrome bug 13".
First, the iframe shows sample.html.
At this point, the title of this tab is still "Chrome bug 13".
Second, please load a PDF document from a link below.
When iframe shows sample.pdf, the title of this tab also changes to "sample.pdf" (wrong behavior).
Since the PDF isn't loaded directly in a whole tab but loaded through iframe, the parent HTML title should not be changed.
On the other hand, the document.title stays to be "Chrome bug 13" (correct behavior).
Then, load the HTML again in iframe from a link below.
Despite showing sample.html again, the title of this tab remains to be "sample.pdf" (wrong behavior).
The document.title holds the value correctly.
This page is related to Issue 966714.