Client Side Speed Index

third_party/WebKit/Source/core/paint/PaintTiming.cpp

Index: third_party/WebKit/Source/core/paint/PaintTiming.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintTiming.cpp b/third_party/WebKit/Source/core/paint/PaintTiming.cpp
index 29b9507d92f900416f65e32390d69d7e04b6269d..b404df422040d2e054629705025bbf284560b9ee 100644
--- a/third_party/WebKit/Source/core/paint/PaintTiming.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintTiming.cpp
@@ -12,6 +12,22 @@
 
 namespace blink {
 
+namespace {
+
+unsigned getRectHash(const IntRect& rect)
+{
+    // Divide by 10 so similar rectangles are treated the same.
+    unsigned positionHash = ((rect.x() / 10) << 16) + (rect.y() / 10);
+    unsigned sizeHash = ((rect.width() / 10) << 16) + (rect.height() / 10);
+    unsigned rectHash = positionHash ^ sizeHash;
+    // HashSets do not allow null values.
+    if (rectHash == 0)
+        rectHash++;
+    return rectHash;
+}
+
+} // namespace
+
 static const char kSupplementName[] = "PaintTiming";
 
 PaintTiming& PaintTiming::from(Document& document)
@@ -27,6 +43,8 @@ PaintTiming& PaintTiming::from(Document& document)
 PaintTiming::PaintTiming(Document& document)
     : m_document(document)
 {
+    ASSERT(document.domWindow());
+    m_viewPortRect = IntRect(0, 0, document.domWindow()->innerWidth(), document.domWindow()->innerHeight());
 }
 
 DEFINE_TRACE(PaintTiming)
@@ -66,4 +84,62 @@ void PaintTiming::markFirstImagePaint()
     notifyPaintTimingChanged();
 }
 
+void PaintTiming::markPaintInvalidation(const IntRect* visualRect, int paintCount)
+{
+    if (m_speedIndex || !m_loadCommitted)
+        return;
+    if (!frame() || !frame()->isMainFrame())
+        return;
+    if (!visualRect->size().area() || !visualRect->intersects(m_viewPortRect))
+        return;
+
+    IntRect intersect = intersection(*visualRect, m_viewPortRect);
+    unsigned rectHash = getRectHash(intersect);
+    unsigned long size = intersect.size().area();
+    double timestamp = monotonicallyIncreasingTime();
+
+    // Don't double count invalidation rects before any painting occurs.
+    if (paintCount != m_lastPaintCount && frameRects.size())
+        frameRects.clear();
+    if (!frameRects.add(rectHash).isNewEntry)
+        return;
+
+    // Add the area under the curve that the previous invalidation rect
+    // contributed.
+    if (m_lastPaintInvalidationTime) {
+        m_totalLoadedArea += (timestamp - m_lastPaintInvalidationTime) * m_totalContributions;
+    }
+    m_lastPaintInvalidationTime = timestamp;
+
+    // Adjust the size of the painted area based on how many times this rect has
+    // been invalidated, as well as if it is a full sized invalidation.
+    double adjustedSize = size;
+    int count = ++(m_rectCounts.add(rectHash, 0).storedValue->value);
+    adjustedSize /= count;
+    if (size == m_viewPortRect.size().area())
+        adjustedSize /= 2.0;
+
+    m_totalContributions += adjustedSize;
+    m_lastPaintCount = paintCount;
+}
+
+double PaintTiming::speedIndex(double referenceTime) const
+{
+    if (m_speedIndex)
+        return m_speedIndex;
+    if (!m_totalContributions)
+        return 0.0;
+
+    double totalArea = (m_lastPaintInvalidationTime - referenceTime) * m_totalContributions;
+    m_speedIndex = (totalArea - m_totalLoadedArea) / m_totalContributions;
+
+    // Unfortunate hack because we can mark invalidations before the first
+    // paint in some circumstances.
+    if (m_firstPaint)
+        m_speedIndex = std::max(m_speedIndex, m_firstPaint - referenceTime);
+
+    TRACE_EVENT2("blink.user_timing", "speedIndex", "value", m_speedIndex * 1000.0, "frame", frame());
+    return m_speedIndex;
+}
+
 } // namespace blink