DevTools: add coverage snapshots

third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp

Index: third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp
diff --git a/third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp b/third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp
index eeec1a0ee119bb7a84418d230a56da78d6e4c868..d82d3e673bbadd36091061504ffcabd7c02652e4 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorCSSAgent.cpp
@@ -2419,19 +2419,18 @@ void InspectorCSSAgent::setUsageTrackerStatus(bool enabled) {
     m_tracker = nullptr;
   }
 
-  HeapVector<Member<Document>> documents = m_domAgent->documents();
-  for (Document* document : documents) {
+  for (Document* document : m_domAgent->documents())
     document->styleEngine().setRuleUsageTracker(m_tracker);
-
-    document->setNeedsStyleRecalc(
-        SubtreeStyleChange,
-        StyleChangeReasonForTracing::create(StyleChangeReason::Inspector));
-  }
 }
 
 Response InspectorCSSAgent::startRuleUsageTracking() {
   m_state->setBoolean(CSSAgentState::ruleRecordingEnabled, true);
   setUsageTrackerStatus(true);
+  for (Document* document : m_domAgent->documents()) {
+    document->setNeedsStyleRecalc(
+        SubtreeStyleChange,
+        StyleChangeReasonForTracing::create(StyleChangeReason::Inspector));
+  }
   return Response::OK();
 }
 
@@ -2449,14 +2448,14 @@ InspectorCSSAgent::buildObjectForRuleUsage(CSSStyleRule* rule, bool used) {
 
 Response InspectorCSSAgent::stopRuleUsageTracking(
     std::unique_ptr<protocol::Array<protocol::CSS::RuleUsage>>* result) {
-  if (!m_tracker) {
+  if (!m_tracker)
     return Response::Error("CSS rule usage tracking is not enabled");
-  }
 
   *result = protocol::Array<protocol::CSS::RuleUsage>::create();
 
   HeapVector<Member<Document>> documents = m_domAgent->documents();
   for (Document* document : documents) {
+    document->updateStyleAndLayoutTree();
     HeapHashSet<Member<CSSStyleSheet>>* newSheetsVector =
         m_documentToCSSStyleSheets.at(document);