SourceEventType added to LatencyInfo

ui/events/latency_info.h

Index: ui/events/latency_info.h
diff --git a/ui/events/latency_info.h b/ui/events/latency_info.h
index c7e69b783fa42b3fb9674d961945b918f4a4705c..606cfd40a39ea9273d983649b092b20c788761ac 100644
--- a/ui/events/latency_info.h
+++ b/ui/events/latency_info.h
@@ -118,6 +118,14 @@ enum LatencyComponentType {
       INPUT_EVENT_LATENCY_TERMINATED_SWAP_FAILED_COMPONENT,
 };
 
+enum SourceEventType {
+  UNKNOWN,
+  WHEEL,
+  TOUCH,
+  OTHER,
+  SOURCE_EVENT_TYPE_LAST = OTHER,
+};
+
 class EVENTS_BASE_EXPORT LatencyInfo {
  public:
   struct LatencyComponent {
@@ -144,6 +152,7 @@ class EVENTS_BASE_EXPORT LatencyInfo {
 
   LatencyInfo();
   LatencyInfo(const LatencyInfo& other);
+  LatencyInfo(SourceEventType type);
   ~LatencyInfo();
 
   // For test only.
@@ -205,6 +214,13 @@ class EVENTS_BASE_EXPORT LatencyInfo {
 
   const LatencyMap& latency_components() const { return latency_components_; }
 
+  const SourceEventType& source_event_type() const {
+    return source_event_type_;
+  }
+  void set_source_event_type(SourceEventType type) {
+    source_event_type_ = type;
+  }
+
   bool terminated() const { return terminated_; }
   void set_coalesced() { coalesced_ = true; }
   bool coalesced() const { return coalesced_; }
@@ -240,6 +256,8 @@ class EVENTS_BASE_EXPORT LatencyInfo {
   bool coalesced_;
   // Whether a terminal component has been added.
   bool terminated_;
+  // Stores the type of the first source event.
+  SourceEventType source_event_type_;
 
 #if !defined(OS_IOS)
   friend struct IPC::ParamTraits<ui::LatencyInfo>;