The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5

commit 68f60f6cfa8d0b968ed9a90e2188dd84c62788e5
Author: valih <valih@google.com>
Date: Fri Nov 04 05:19:21 2016

- backend code for css rule tracking
- 2 new browser protocol functions : "startRuleUsageTracking" and "stopRuleUsageTracking" that also returns the rule usage list.

BUG= 662260 

Review-Url: https://codereview.chromium.org/2455943003
Cr-Commit-Position: refs/heads/master@{#429792}

[add] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/LayoutTests/inspector-protocol/css/css-get-rule-list-expected.txt
[add] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/LayoutTests/inspector-protocol/css/css-get-rule-list.html
[add] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/LayoutTests/inspector-protocol/css/resources/get-rule-list.css
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/BUILD.gn
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/ElementRuleCollector.cpp
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/ElementRuleCollector.h
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/resolver/StyleResolver.h
[add] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/resolver/StyleRuleUsageTracker.cpp
[add] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/css/resolver/StyleRuleUsageTracker.h
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/dom/StyleEngine.cpp
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/dom/StyleEngine.h
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/InspectorCSSAgent.h
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/InspectorDOMAgent.cpp
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/InspectorDOMAgent.h
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/InspectorStyleSheet.cpp
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/InspectorStyleSheet.h
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/core/inspector/browser_protocol.json
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js
[modify] https://crrev.com/68f60f6cfa8d0b968ed9a90e2188dd84c62788e5/third_party/WebKit/Source/devtools/front_end/sdk/CSSRule.js