Add latency measurement system

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index 55f6452ded8bc55344b72f71dc08478de00335a7..96b1bd6ac613e50e2e152e59ed2c4e6acfe48449 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -317,6 +317,7 @@ OutputSurface* LayerTreeHostImpl::outputSurface() const
 
 void LayerTreeHostImpl::animate(base::TimeTicks monotonicTime, base::Time wallClockTime)
 {
+    setLatencyInfo(LatencyInfo());
     animatePageScale(monotonicTime);
     animateLayers(monotonicTime, wallClockTime);
     animateScrollbars(monotonicTime);
@@ -938,10 +939,29 @@ bool LayerTreeHostImpl::swapBuffers()
 {
     DCHECK(m_renderer);
 
+    m_createdFrame = false;
+    TRACE_EVENT_ASYNC_END2("cc", "Frame", this, "implFrameNumber", m_latencyInfo.rendererImplFrameNumber, "mainFrameNumber", m_latencyInfo.rendererMainFrameNumber);
+    TRACE_EVENT_INSTANT1("cc", "Frame", "inputNumber", m_latencyInfo.inputNumber);
     m_fpsCounter->markEndOfFrame();
     return m_renderer->swapBuffers();
 }
 
+void LayerTreeHostImpl::setLatencyInfo(const LatencyInfo& latency_info) {
+    m_latencyInfo.rendererMainFrameNumber = std::max(latency_info.rendererMainFrameNumber, m_latencyInfo.rendererMainFrameNumber);
+    m_latencyInfo.rendererImplFrameNumber = std::max(latency_info.rendererImplFrameNumber, m_latencyInfo.rendererImplFrameNumber);
+    m_latencyInfo.inputNumber = std::max(latency_info.inputNumber, m_latencyInfo.inputNumber);
+    if (!m_createdFrame) {
+        m_createdFrame = true;
+        m_latencyInfo.rendererImplFrameNumber++;
+        TRACE_EVENT_ASYNC_BEGIN2("cc", "Frame", this, "implFrameNumber", m_latencyInfo.rendererImplFrameNumber, "mainFrameNumber", m_latencyInfo.rendererMainFrameNumber);
+    }
+    m_outputSurface->SetLatencyInfo(m_latencyInfo);
+}
+
+void LayerTreeHostImpl::OnReceivedLatencyInfo(const LatencyInfo& latency_info) {
+    m_client->onReceivedLatencyInfo(latency_info);
+}
+
 const gfx::Size& LayerTreeHostImpl::deviceViewportSize() const
 {
     return m_deviceViewportSize;
@@ -1332,7 +1352,8 @@ static gfx::Vector2dF scrollLayerWithLocalDelta(LayerImpl& layerImpl, gfx::Vecto
     return layerImpl.scrollDelta() - previousDelta;
 }
 
-bool LayerTreeHostImpl::scrollBy(const gfx::Point& viewportPoint,
+bool LayerTreeHostImpl::scrollBy(int64 input_number,
+                                 const gfx::Point& viewportPoint,
                                  const gfx::Vector2d& scrollDelta)
 {
     TRACE_EVENT0("cc", "LayerTreeHostImpl::scrollBy");
@@ -1380,6 +1401,9 @@ bool LayerTreeHostImpl::scrollBy(const gfx::Point& viewportPoint,
     }
 
     if (didScroll) {
+        LatencyInfo latency_info;
+        latency_info.inputNumber = input_number;
+        setLatencyInfo(latency_info);
         m_client->setNeedsCommitOnImplThread();
         m_client->setNeedsRedrawOnImplThread();
         setNeedsUpdateDrawProperties();