GPU benchmarks should track the frequency of impl-thread vs. main-thread scrolls

cc/CCLayerTreeHostImpl.cpp

 // Copyright 2011 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.
 
 #include "config.h"
 
 #include "CCLayerTreeHostImpl.h"
 
 #include "base/basictypes.h"
 #include "CCAppendQuadsData.h"
@@ skipping 113 matching lines @@
     , m_pageScaleDelta(1)
     , m_sentPageScaleDelta(1)
     , m_minPageScale(0)
     , m_maxPageScale(0)
     , m_backgroundColor(0)
     , m_hasTransparentBackground(false)
     , m_needsAnimateLayers(false)
     , m_pinchGestureActive(false)
     , m_fpsCounter(CCFrameRateCounter::create())
     , m_debugRectHistory(CCDebugRectHistory::create())
+    , m_numImplThreadScrolls(0)
+    , m_numMainThreadScrolls(0)
 {
     ASSERT(CCProxy::isImplThread());
     didVisibilityChange(this, m_visible);
 }
 
 CCLayerTreeHostImpl::~CCLayerTreeHostImpl()
 {
     ASSERT(CCProxy::isImplThread());
     TRACE_EVENT0("cc", "CCLayerTreeHostImpl::~CCLayerTreeHostImpl()");
 
@@ skipping 774 matching lines @@
     deviceViewportPoint.scale(m_deviceScaleFactor, m_deviceScaleFactor);
 
     // First find out which layer was hit from the saved list of visible layers
     // in the most recent frame.
     CCLayerImpl* layerImpl = CCLayerTreeHostCommon::findLayerThatIsHitByPoint(viewportPoint, m_renderSurfaceLayerList);
 
     // Walk up the hierarchy and look for a scrollable layer.
     CCLayerImpl* potentiallyScrollingLayerImpl = 0;
     for (; layerImpl; layerImpl = layerImpl->parent()) {
         // The content layer can also block attempts to scroll outside the main thread.
-        if (layerImpl->tryScroll(deviceViewportPoint, type) == ScrollOnMainThread)
+        if (layerImpl->tryScroll(deviceViewportPoint, type) == ScrollOnMainThread) {
+            m_numMainThreadScrolls++;
             return ScrollOnMainThread;
+        }
 
         CCLayerImpl* scrollLayerImpl = findScrollLayerForContentLayer(layerImpl);
         if (!scrollLayerImpl)
             continue;
 
         ScrollStatus status = scrollLayerImpl->tryScroll(viewportPoint, type);
 
         // If any layer wants to divert the scroll event to the main thread, abort.
-        if (status == ScrollOnMainThread)
+        if (status == ScrollOnMainThread) {
+            m_numMainThreadScrolls++;
             return ScrollOnMainThread;
+        }
 
         if (status == ScrollStarted && !potentiallyScrollingLayerImpl)
             potentiallyScrollingLayerImpl = scrollLayerImpl;
     }
 
     if (potentiallyScrollingLayerImpl) {
         m_currentlyScrollingLayerImpl = potentiallyScrollingLayerImpl;
         // Gesture events need to be transformed from screen coordinates to local layer coordinates
         // so that the scrolling contents exactly follow the user's finger. In contrast, wheel
         // events are already in local layer coordinates so we can just apply them directly.
         m_scrollDeltaIsInScreenSpace = (type == Gesture);
+        m_numImplThreadScrolls++;
         return ScrollStarted;
     }
     return ScrollIgnored;
 }
 
 static FloatSize scrollLayerWithScreenSpaceDelta(CCLayerImpl& layerImpl, const FloatPoint& screenSpacePoint, const FloatSize& screenSpaceDelta)
 {
     // Layers with non-invertible screen space transforms should not have passed the scroll hit
     // test in the first place.
     ASSERT(layerImpl.screenSpaceTransform().isInvertible());
@@ skipping 331 matching lines @@
 
 int CCLayerTreeHostImpl::sourceAnimationFrameNumber() const
 {
     return fpsCounter()->currentFrameNumber();
 }
 
 void CCLayerTreeHostImpl::renderingStats(CCRenderingStats* stats) const
 {
     stats->numFramesSentToScreen = fpsCounter()->currentFrameNumber();
     stats->droppedFrameCount = fpsCounter()->droppedFrameCount();
+    stats->numImplThreadScrolls = m_numImplThreadScrolls;
+    stats->numMainThreadScrolls = m_numMainThreadScrolls;
 }
 
 void CCLayerTreeHostImpl::animateScrollbars(double monotonicTime)
 {
     animateScrollbarsRecursive(m_rootLayerImpl.get(), monotonicTime);
 }
 
 void CCLayerTreeHostImpl::animateScrollbarsRecursive(CCLayerImpl* layer, double monotonicTime)
 {
     if (!layer)
         return;
 
     CCScrollbarAnimationController* scrollbarController = layer->scrollbarAnimationController();
     if (scrollbarController && scrollbarController->animate(monotonicTime))
         m_client->setNeedsRedrawOnImplThread();
 
     for (size_t i = 0; i < layer->children().size(); ++i)
         animateScrollbarsRecursive(layer->children()[i], monotonicTime);
 }
 
 } // namespace cc