This is regression issue broken in M51. Below are the bisect details below:

Good Build: 51.0.2703.0
Bad Build: 51.0.2704.0

Change Log URL: https://chromium.googlesource.com/chromium/src/+log/51.0.2703.0..51.0.2704.0?pretty=fuller&n=10000

Suspecting #386027 or #386214 could be the possible culprits 

Change URL: https://chromium.googlesource.com/chromium/src/+/95977a2105324fb9a790db999441bd5891c4e671

or

Change URL: https://chromium.googlesource.com/chromium/src/+/736ad8abed54d7393cf672f4dbc2eea26e08bdcf

@ ccameron or @cwallez, request you to please take a look into it. Please help us to reassign if not with respect to your change.

Note: This issue happens for a First and Clean installation.

just to update,
over install is working fine (able to launch chrome)

Ranjith , can u please try a chromium bisect and narrow down further.

Tried the same using chromium builds using bisect script and manually and observed that all the chromium builds invoked are launching.

Chrome is crashing at startup, requesting help from Stability Sheriff to confirm the CLs mentioned in #1 and revert the patch.

This is a blocker for tomorrow Dev channel release.

Chrome stability sheriff here.

If by "over install" you mean a *non* fresh install (ie with an existing user data dir), then the problem might be launching Chrome with a new profile. Can you try the bisect again passing --user-data-dir=/tmp/a1 with a different user data dir each time (a1, a2, ... etc.)?

Ligi reports this is crashing with Trace/BPT trap: 5 when running from the terminal.

Error from Console
==================
Apr 11 23:34:24 ligimole-macbookair kernel[0]: Google Chrome[14021] triggered unnest of range 0x7fff90800000->0x7fff90a00000 of DYLD shared region in VM map 0xe7a025ada6e3d703. While not abnormal for debuggers, this increases system memory footprint until the target exits.
Apr 11 23:34:24 ligimole-macbookair kernel[0]: Google Chrome He[14027] triggered unnest of range 0x7fff90800000->0x7fff90a00000 of DYLD shared region in VM map 0xe7a025ada0dded4b. While not abnormal for debuggers, this increases system memory footprint until the target exits.
Apr 11 23:34:27 ligimole-macbookair ReportCrash[14029]: Saved crash report for Google Chrome[14021] version 51.0.2704.4 (2704.4) to /Users/ligimole/Library/Logs/DiagnosticReports/Google Chrome_2016-04-11-233427_ligimole-macbookair.crash

Attaching the log file.

Deleted: console_log.png 170 KB

	console_log.png 170 KB View Download

This may be Issue 582840.

Here's a crash query that indicates all the crashes seen from that dev candidate have the magic signature of Issue 582840. Best to move discussion to that issue.

https://crash.corp.google.com/dremel_query_ui?q=SELECT%20g.channel%2C%20g.product.version%2C%20specific%2C%20general%2C%20specific%20%2F%20general%0AFROM%20(%0ASELECT%20channel%2C%20product.version%2C%20COUNT(*)%20as%20specific%0AFROM%20crash.prod.latest%0AWHERE%20product.name%20%3D%20%22Chrome_Mac%22%0AAND%20custom_data.ChromeCrashProto.ptype%3D%22browser%22%0AAND%20custom_data.ChromeCrashProto.magic_signature_1.name%3D%22%5BAssert%5D%20ChromeBrowserMainPartsMac%3A%3APostProfileInit%22%0AGROUP%20BY%201%2C%202)%20AS%20s%0ALEFT%20OUTER%20JOIN%20(%0ASELECT%20channel%2C%20product.version%2C%20COUNT(*)%20as%20general%0AFROM%20crash.prod.latest%0AWHERE%20product.name%20%3D%20%22Chrome_Mac%22%0AAND%20custom_data.ChromeCrashProto.ptype%3D%22browser%22%0AGROUP%20BY%201%2C%202)%20AS%20g%0AON%20s.channel%20%3D%20g.channel%20AND%20s.product.version%20%3D%20g.product.version%0AORDER%20BY%202%20DESC%2C%201

I think, the change: https://chromium.googlesource.com/chromium/src/+/e930129c9456bf90b7c97844076ddf3b077d3a87%5E%21/ probably causes this issue.