Chromium downloads a blob related to the hotword module without user request. This bug was already reported here (https://code.google.com/p/chromium/issues/detail?id=491435).
The symptoms are obtained with the following version of chromium (default options) :
Name : chromium
Version : 43.0.2357.125
At first launch, files are automatically downloaded as shown by the following output (just after a rm -Rf .config/chromium):
$ ls -l $HOME/.config/chromium/Default/Extensions/lccekmodgklaepjeofjdjpbminllajkg/0.3.0.5_0/_platform_specific/x86-64_
-rw------- 1 hukadan hukadan 1181296 Jun 5 23:54 hotword-x86-64.nexe
-rw------- 1 hukadan hukadan 896976 Jun 5 23:54 hotword.data
Going to the following address chrome://voicesearch/, the following information are displayed:
About Voice Search
Chromium 43.0.2357.125 ()
NaCl Enabled No
Audio Capture Allowed Yes
Current Language en-US
Hotword Previous Language en-US
Hotword Search Enabled No
Always-on Hotword Search Enabled No
Hotword Audio Logging Enabled No
Start Page State No Start Page Service
Extension Id nbpagnldghgfoolbancepceaanlmhfmd
Extension Version 0.0.1.4
Extension Path /usr/local/share/chromium/resources/hotword
Extension State ENABLED
Shared Module Id lccekmodgklaepjeofjdjpbminllajkg
Shared Module Version 0.3.0.5
Shared Module Path /home/hukadan/.config/chromium/Default/Extensions/lccekmodgklaepjeofjdjpbminllajkg/0.3.0.5_0
Shared Module State ENABLED
Shared Module Platforms x86-64_
A commit was done (https://chromium.googlesource.com/chromium/src.git/+/f269d3b548203e217e8c0080c2e22e7ae3efb51e) to make a flag available in order to disable this downloading. The flag seems not to be available yet with the port version of chromium.
Would it be possible to make it available ?
As an update (43.0.2357.132) doesn't have the flag yet.
May or may not be related to this: Is anyone else experiencing an Alert-like dialog if they attempt to close chromium with nothing downloading?
I think we can safely close this bug report. The problem is not reproducible anymore on my system. Furthermore, the hotword module has been disabled by default upstream : https://chromium.googlesource.com/chromium/src.git/+/0366a5184a70b3eefb5fcef2c2e13721669f00d8.