Track plugin input event latency

content/renderer/pepper/pepper_plugin_instance_impl.cc

Index: content/renderer/pepper/pepper_plugin_instance_impl.cc
diff --git a/content/renderer/pepper/pepper_plugin_instance_impl.cc b/content/renderer/pepper/pepper_plugin_instance_impl.cc
index d79c9f96630f73cfa6955beb71b592498802292d..711a7e9424ece1abe979e536b2f1e6fd28099a0e 100644
--- a/content/renderer/pepper/pepper_plugin_instance_impl.cc
+++ b/content/renderer/pepper/pepper_plugin_instance_impl.cc
@@ -16,7 +16,9 @@
 #include "base/strings/utf_offset_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
+#include "cc/base/latency_info_swap_promise.h"
 #include "cc/layers/texture_layer.h"
+#include "cc/trees/layer_tree_host.h"
 #include "content/common/content_constants_internal.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/page_zoom.h"
@@ -1094,8 +1096,22 @@ bool PepperPluginInstanceImpl::HandleInputEvent(
         pending_user_gesture_token_.setOutOfProcess();
       }
 
+      const ui::LatencyInfo* current_event_latency_info = NULL;
+      if (render_frame_->GetRenderWidget()) {
+        current_event_latency_info =
+            render_frame_->GetRenderWidget()->current_event_latency_info();

[piman, 2014/04/25 01:59:43]

In the future (e.g. after the blink merge), I'm hoping the LatencyInfo can stay
together with the WebInputEvent as it flows through webkit. This is a bit of a
hack for now...

[Yufeng Shen (Slow to review), 2014/04/25 20:42:42]

Right. I always want to couple WebInputEvent with LatencyInfo so we have more
latency coverage along the input path. It's just this requires more plumbing
rework and need a stronger use case to convince the blink reviewer. That's why I
take this hacky solution in this CL. 

+      }
+
       // Each input event may generate more than one PP_InputEvent.
       for (size_t i = 0; i < events.size(); i++) {
+        if (current_event_latency_info) {
+          events[i].latency_info.CopyLatencyFrom(
+              *current_event_latency_info,
+              ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT);
+          events[i].latency_info.CopyLatencyFrom(
+              *current_event_latency_info,
+              ui::INPUT_EVENT_LATENCY_UI_COMPONENT);
+        }
         if (filtered_input_event_mask_ & event_class)
           events[i].is_filtered = true;
         else
@@ -1983,6 +1999,20 @@ bool PepperPluginInstanceImpl::PrepareTextureMailbox(
 
 void PepperPluginInstanceImpl::OnDestruct() { render_frame_ = NULL; }
 
+void PepperPluginInstanceImpl::AddLatencyInfo(
+    const std::vector<ui::LatencyInfo>& latency_info) {
+  if (texture_layer_) {
+    cc::LayerTreeHost* layer_tree_host = texture_layer_->layer_tree_host();

[piman, 2014/04/25 01:59:43]

I'd rather we went to the compositor via the RenderWidget, otherwise this is
racy.
When newly created, the TextureLayer won't be added to the tree until the next
layout, meaning its LTH will be NULL.

Maybe ideally, we'd go through
RenderWidgetCompositor::CreateLatencyInfoSwapPromiseMonitor like
RenderWidget::OnHandleInputEvent

[Yufeng Shen (Slow to review), 2014/04/25 20:42:42]

done.
It now goes through render_frame_->GetRenderWidget()->compositor()

+    if (layer_tree_host) {
+      for (size_t i = 0; i < latency_info.size(); i++) {
+        scoped_ptr<cc::SwapPromise> swap_promise(
+            new cc::LatencyInfoSwapPromise(latency_info[i]));
+        layer_tree_host->QueueSwapPromise(swap_promise.Pass());
+      }
+    }
+  }
+}
+
 void PepperPluginInstanceImpl::AddPluginObject(PluginObject* plugin_object) {
   DCHECK(live_plugin_objects_.find(plugin_object) ==
          live_plugin_objects_.end());