Change input latency result to depend on start of GPU swap

content/common/gpu/image_transport_surface.cc

Index: content/common/gpu/image_transport_surface.cc
diff --git a/content/common/gpu/image_transport_surface.cc b/content/common/gpu/image_transport_surface.cc
index 7e01bc13f7952607375e06536442decbd91f85eb..b86be03ef497cfe154f9931f91af083d8cab85bc 100644
--- a/content/common/gpu/image_transport_surface.cc
+++ b/content/common/gpu/image_transport_surface.cc
@@ -203,8 +203,12 @@ bool PassThroughImageTransportSurface::SwapBuffers() {
   // GetVsyncValues before SwapBuffers to work around Mali driver bug:
   // crbug.com/223558.
   SendVSyncUpdateIfAvailable();
-  for (auto& latency : latency_info_)
-    latency.AddLatencyNumber(ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, 0, 0);
+
+  base::TimeTicks swap_time = base::TimeTicks::Now();
+  for (auto& latency : latency_info_) {
+    latency.AddLatencyNumberWithTimestamp(
+        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, 0, 0, swap_time, 1);
+  }
 
   // We use WeakPtr here to avoid manual management of life time of an instance
   // of this class. Callback will not be called once the instance of this class
@@ -218,6 +222,13 @@ bool PassThroughImageTransportSurface::SwapBuffers() {
 bool PassThroughImageTransportSurface::PostSubBuffer(
     int x, int y, int width, int height) {
   SendVSyncUpdateIfAvailable();
+
+  base::TimeTicks swap_time = base::TimeTicks::Now();
+  for (auto& latency : latency_info_) {
+    latency.AddLatencyNumberWithTimestamp(
+        ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, 0, 0, swap_time, 1);
+  }
+
   // We use WeakPtr here to avoid manual management of life time of an instance
   // of this class. Callback will not be called once the instance of this class
   // is destroyed. However, this also means that the callback can be run on
@@ -228,9 +239,11 @@ bool PassThroughImageTransportSurface::PostSubBuffer(
 }
 
 void PassThroughImageTransportSurface::SwapBuffersCallBack() {
-  for (size_t i = 0; i < latency_info_.size(); i++) {
-    latency_info_[i].AddLatencyNumber(
-        ui::INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT, 0, 0);
+  base::TimeTicks swap_ack_time = base::TimeTicks::Now();
+  for (auto& latency : latency_info_) {
+    latency.AddLatencyNumberWithTimestamp(
+        ui::INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT, 0, 0,
+        swap_ack_time, 1);
   }
 
   helper_->SwapBuffersCompleted(latency_info_);