Marking this a TLS 1.3 blocker since we will indeed be redoing cipher suite negotiation in 1.3. That or we just hardcode key exchange to always show "ECDHE" which isn't very useful. No rush right now, but I want to keep track of the 1.3 blockers.

I've largely got this working now. Should be ready soon.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/960cd60330949cbfc0af26e25aa5d061cdec534c

commit 960cd60330949cbfc0af26e25aa5d061cdec534c
Author: davidben <davidben@chromium.org>
Date: Fri Sep 09 07:38:00 2016

Route key_exchange_group over to DevTools.

This replaces key_exchange_info with key_exchange_group at all layers
but net::SSLInfo, fixing key_exchange_info's type issues. Then we route
it over to DevTools as an optional new field "Key Exchange Group".

Later work, once the TLS 1.3 draft 15 negotiation is implemented, will
make the DevTools able to handle missing key_exchange. In 1.3, what
DevTools currently calls a "Key Exchange" isn't really meaningful and
is just described by the group. ( https://crbug.com/639495 )

Screenshots:
https://drive.google.com/folderview?id=0Bz14lOW5Hke4VFlBVXJOY0Z0cUU&usp=sharing

(Note: the TLS 1.3 picture is a mock of how it will look when the
new cipher suite negotiation is implemented and a second change made.)

BUG= 639421 , 618035 

Review-Url: https://codereview.chromium.org/2272603003
Cr-Commit-Position: refs/heads/master@{#417527}

[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/chrome/app/generated_resources.grd
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/chrome/browser/ssl/chrome_security_state_model_client.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/chrome/browser/ssl/chrome_security_state_model_client_browser_tests.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/chrome/browser/ssl/chrome_security_state_model_client_unittest.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/components/security_state/security_state_model.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/components/security_state/security_state_model.h
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/content/browser/loader/resource_loader.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/content/child/web_url_loader_impl.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/content/common/resource_messages.h
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/content/public/common/resource_response_info.h
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/content/public/common/ssl_status.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/content/public/common/ssl_status.h
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/net/quic/chromium/quic_chromium_client_session.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/net/ssl/ssl_info.cc
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/net/ssl/ssl_info.h
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/Source/core/inspector/InspectorNetworkAgent.cpp
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/Source/core/inspector/browser_protocol.json
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/Source/devtools/front_end/security/SecurityPanel.js
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/Source/platform/exported/WebURLResponse.cpp
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/Source/platform/network/ResourceResponse.cpp
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/Source/platform/network/ResourceResponse.h
[modify] https://crrev.com/960cd60330949cbfc0af26e25aa5d061cdec534c/third_party/WebKit/public/platform/WebURLResponse.h