Moved issue gerrit:5136 to now be  issue chromium:674254 .

So the rietveld behavior is this:
* If you're creating a new issue and don't specify a message, it defaults to title (if specified) plus recent commit history (and opens an editor to confirm)
* If you don't specify a title, it defaults to first line of message
* If you don't specify that, it defaults to the first line of the most recent commit (and prompts to confirm)
* If you don't specify a message, the message becomes the same as the title
* If you're creating a new issue:
  * title becomes the issue title
  * message becomes the issue commit message
  * whitespace becomes the patchset description
* If you're uploading a new patchset to an existing issue:
  * title becomes the patchset description
  * message becomes the body of the email message

The gerrit behavior is close but not quite the same. It is:
* If you're creating a new issue:
  * if you don't specify a message, it defaults to recent commit history (and opens an editor to confirm)
  * if you don't specify a title, it defaults to 'Initial upload'
  * message becomes the commit description
  * first line of message becomes the CL title
  * title becomes the patchset description
* If you're uploading a patchset to an existing issue:
  * if you don't specify a title, it defaults to the first line of the most recent commit message (and prompts to confirm)
  * title becomes the patchset description
  * message is ignored

So the things that need to be fixed are:
* Gerrit needs to prepend title to message before opening an editor to confirm
* If you specify a message for non-initial upload, it should send an email

Here's a CL for the former: https://chromium-review.googlesource.com/425823
And I'm not going to fix the latter because few people use it and gerrit doesn't support it anyway.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools.git/+/b56ad33d008b7589b20f853c3126d89760a4e508

commit b56ad33d008b7589b20f853c3126d89760a4e508
Author: Aaron Gable <agable@chromium.org>
Date: Fri Jan 06 23:24:31 2017

Respect -t/--title in initial cl uploads to Gerrit

BUG= 674254 

Change-Id: Icdc572648dfffeca7e28f327e085f64985221ce9
Reviewed-on: https://chromium-review.googlesource.com/425823
Commit-Queue: Aaron Gable <agable@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>

[modify] https://crrev.com/b56ad33d008b7589b20f853c3126d89760a4e508/git_cl.py
[modify] https://crrev.com/b56ad33d008b7589b20f853c3126d89760a4e508/tests/git_cl_test.py