Visual viewport API initial implementation.

third_party/WebKit/Source/core/frame/VisualViewport.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 67 matching lines @@
 {
     sendUMAMetrics();
 }
 
 DEFINE_TRACE(VisualViewport)
 {
     visitor->trace(m_frameHost);
     ScrollableArea::trace(visitor);
 }
 
+void VisualViewport::updateLayoutIgnorePendingStylesheets()
+{
+    if (!mainFrame())
+        return;
+
+    Document* document = mainFrame()->document();
+    if (!document)
+        return;
+
+    document->updateLayoutIgnorePendingStylesheets();
+    return;
+}
+
+void VisualViewport::dispatchChangedEvent()
+{
+    if (RuntimeEnabledFeatures::visualViewportAPIEnabled()) {
+        if (Document* document = mainFrame()->document())
+            document->dispatchVisualViewportChangedEvent();
+    }
+}
+
 void VisualViewport::setSize(const IntSize& size)
 {
     if (m_size == size)
         return;
 
     TRACE_EVENT2("blink", "VisualViewport::setSize", "width", size.width(), "height", size.height());
     bool widthDidChange = size.width() != m_size.width();
     m_size = size;
 
     if (m_innerViewportContainerLayer) {
         m_innerViewportContainerLayer->setSize(FloatSize(m_size));
 
         // Need to re-compute sizes for the overlay scrollbars.
         initializeScrollbars();
     }
 
     if (!mainFrame())
         return;
 
+    dispatchChangedEvent();

[bokan, 2016/03/22 18:30:29]

Hmm...right now we're firing events synchronously. I wonder if we should
coalesce them and fire one at the beginning of each frame? Lets do that in a
follow up if needed.

[ymalik, 2016/03/22 21:28:20]

Acknowledged.

+
     bool autosizerNeedsUpdating = widthDidChange
         && mainFrame()->settings()
         && mainFrame()->settings()->textAutosizingEnabled();
 
     if (autosizerNeedsUpdating) {
         // This needs to happen after setting the m_size member since it'll be read in the update call.
         if (TextAutosizer* textAutosizer = mainFrame()->document()->textAutosizer())
             textAutosizer->updatePageInfoInAllFrames();
     }
 }
@@ skipping 65 matching lines @@
 void VisualViewport::move(const FloatSize& delta)
 {
     setLocation(m_offset + delta);
 }
 
 void VisualViewport::setScale(float scale)
 {
     setScaleAndLocation(scale, m_offset);
 }
 
+double VisualViewport::scrollLeft()
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    return visibleRect().x();
+}
+
+double VisualViewport::scrollTop()
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    return visibleRect().y();
+}
+
+void VisualViewport::setScrollLeft(double x)
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    DoublePoint layoutPos(x, visibleRect().y());
+    setScrollPosition(layoutPos, ProgrammaticScroll, ScrollBehaviorAuto);
+}
+
+void VisualViewport::setScrollTop(double y)
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    DoublePoint layoutPos(visibleRect().x(), y);
+    setScrollPosition(layoutPos, ProgrammaticScroll, ScrollBehaviorAuto);
+}
+
+double VisualViewport::clientWidth()
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    return visibleRect().width();
+}
+
+double VisualViewport::clientHeight()
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    return visibleRect().height();
+}
+
+double VisualViewport::pageScale()
+{
+    updateLayoutIgnorePendingStylesheets();
+
+    return m_scale;
+}
+
 void VisualViewport::setScaleAndLocation(float scale, const FloatPoint& location)
 {
     if (!mainFrame())
         return;
 
     bool valuesChanged = false;
 
     if (scale != m_scale) {
         m_scale = scale;
         valuesChanged = true;
@@ skipping 15 matching lines @@
                 document->enqueueScrollEventForNode(document);
         }
 
         mainFrame()->loader().client()->didChangeScrollOffset();
         valuesChanged = true;
     }
 
     if (!valuesChanged)
         return;
 
+    dispatchChangedEvent();
+
     InspectorInstrumentation::didUpdateLayout(mainFrame());
     mainFrame()->loader().saveScrollState();
 
     clampToBoundaries();
 }
 
 bool VisualViewport::magnifyScaleAroundAnchor(float magnifyDelta, const FloatPoint& anchor)
 {
     const float oldPageScale = scale();
     const float newPageScale = frameHost().chromeClient().clampPageScaleFactorToLimits(
@@ skipping 506 matching lines @@
     } else if (graphicsLayer == m_rootTransformLayer) {
         name =  "Root Transform Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink