Thanks for the report.

Able to reproduce the issue on Win7, Mac OS X 10.11.3, Ubuntu 14.04 using Chrome Stable 49.0.2623.110, Beta 50.0.2661.57, Dev 51.0.2693.2 and Canary # 51.0.2695.1

Not a regression issue, existing from M18 builds #18.0.1000.0
Note: 
1. PDF loaded properly in FF 45.0.1, IE 11
2. Other PDFs are loaded normally in Chrome, tried the below PDFs
http://www.polyu.edu.hk/iaee/files/pdf-sample.pdf
http://hotelpodlipou.sk/uploads/files/sample.pdf
http://www.princexml.com/samples/catalog/PrinceCatalogue.pdf

Requesting Dev team to check the issue and update.

Same problem with Windows 7, Chrome 49.0.2623.110.
Not a single PDF is displayed, ok within all other browsers.

Downloading the PDF and opening in Chrome works correctly and quickly. This seems to be an issue with requesting the document from the server.

tsergeant@ can you take a look or pass off to the right owner?

I'm able to reproduce on Windows (M52 and M50) but not on Linux or ChromeOS.

Passing on to raymes@ for PDF plugin know-how.

thestig: could you help us triage? Thanks!

I get the half way loaded behavior with 51.0.2700.0 on Linux.

spelchat: Interested in taking a look?

This actually works fine in 49.0.2623.110 (64-bit) Ubuntu 14.04, but not in 50.0.2661.75 beta (64-bit). This is probably due to the range requests Chrome is making. I'll have a look.

Chrome make a full request. Cancels it, makes a first range request. It gets a proper response. Then makes another range request and the server hangs for 300s, then responds with a 504.

Here's part of the netlog for the last range request:

t=  7588 [st=     1]        HTTP_TRANSACTION_SEND_REQUEST_HEADERS
                            --> GET /docs/default-source/Publications/20160216_rie2020-overview.pdf?sfvrsn=0 HTTP/1.1
                                Host: www.nrf.gov.sg
                                Connection: keep-alive
                                User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.75 Safari/537.36
                                Accept: */*
                                Referer: http://www.nrf.gov.sg/docs/default-source/Publications/20160216_rie2020-overview.pdf?sfvrsn=0
                                Accept-Encoding: gzip, deflate, sdch
                                Accept-Language: en-US,en;q=0.8
                                Cookie: [115 bytes were stripped]
                                Range: bytes=329478-395013
t=  7588 [st=     1]     -HTTP_TRANSACTION_SEND_REQUEST
t=  7588 [st=     1]     +HTTP_TRANSACTION_READ_HEADERS  [dt=300210]
t=  7588 [st=     1]        HTTP_STREAM_PARSER_READ_HEADERS  [dt=300210]
t=307798 [st=300211]        HTTP_TRANSACTION_READ_RESPONSE_HEADERS
                            --> HTTP/1.1 504 Gateway Time-out
                                Date: Fri, 15 Apr 2016 15:46:34 GMT
                                Content-Type: text/html
                                Content-Length: 6489
                                Connection: keep-alive
                                Keep-Alive: timeout=20
                                ETag: "5604c5ba-1959"
                                Server: DOSarrest

Making the request with curl gives the same result. We should make Chrome display an error message, but otherwise there's not much we can do, the server is broken.

The PDF loads for me with Chrome 56. Not sure what changed.