Add input coordinate information to InputLatency

ui/events/latency_info.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_EVENTS_LATENCY_INFO_H_
 #define UI_EVENTS_LATENCY_INFO_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 80 matching lines @@
     int64 sequence_number;
     // Average time of events that happened in this component.
     base::TimeTicks event_time;
     // Count of events that happened in this component
     uint32 event_count;
   };
 
   // Empirically determined constant based on a typical scroll sequence.
   enum { kTypicalMaxComponentsPerLatencyInfo = 6 };
 
+  enum { kMaxInputCoordinates = 2 };
+  enum { kCoordinateDimensions = 2 };
+

[jdduke (slow), 2014/09/17 17:43:34]

If we can't use gfx::PointF, would this benefit from

struct LatencyCoordinate {
  LatencyCoordinate();
  float x, y;
};

?

[Sami, 2014/09/18 14:52:37]

Yes, that brings some well needed structure.

+  typedef float InputCoordinates[kMaxInputCoordinates][kCoordinateDimensions];
+
   // Map a Latency Component (with a component-specific int64 id) to a
   // component info.
   typedef base::SmallMap<
       std::map<std::pair<LatencyComponentType, int64>, LatencyComponent>,
       kTypicalMaxComponentsPerLatencyInfo> LatencyMap;
 
   LatencyInfo();
 
   ~LatencyInfo();
 
@@ skipping 34 matching lines @@
                    int64 id,
                    LatencyComponent* output) const;
 
   void RemoveLatency(LatencyComponentType type);
 
   void Clear();
 
   // Records the |event_type| in trace buffer as TRACE_EVENT_ASYNC_STEP.
   void TraceEventType(const char* event_type);
 
   LatencyMap latency_components;

[jdduke (slow), 2014/09/17 17:43:34]

Are all these members public to simplify serialization? Seems rather unfortunate
:(

[Sami, 2014/09/18 14:52:37]

I guess that is the reason. Everything else mostly uses methods to access the
same data.

+
+  // These coordinates represent window coordinates of the original input event.
+  size_t input_coordinates_size;
+  InputCoordinates input_coordinates;
+
   // The unique id for matching the ASYNC_BEGIN/END trace event.
   int64 trace_id;
   // Whether a terminal component has been added.
   bool terminated;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_LATENCY_INFO_H_