Visual viewport API initial implementation.

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

Index: third_party/WebKit/Source/core/frame/VisualViewport.cpp
diff --git a/third_party/WebKit/Source/core/frame/VisualViewport.cpp b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
index 36f962068c3dd39c9ee25752b4aa7b901fa75685..06bf34f97786c519f17f3f3d758e1e6bebc5b96e 100644
--- a/third_party/WebKit/Source/core/frame/VisualViewport.cpp
+++ b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
@@ -87,6 +87,19 @@ DEFINE_TRACE(VisualViewport)
     ScrollableArea::trace(visitor);
 }
 
+void VisualViewport::updateLayoutIgnorePendingStylesheets()
+{
+    if (!mainFrame())
+        return;
+
+    Document* document = mainFrame()->document();
+    if (!document)
+        return;
+
+    document->updateLayoutIgnorePendingStylesheets();
+    return;
+}
+
 void VisualViewport::setSize(const IntSize& size)
 {
     if (m_size == size)
@@ -191,6 +204,57 @@ void VisualViewport::setScale(float scale)
     setScaleAndLocation(scale, m_offset);
 }
 
+double VisualViewport::scrollLeft()
+{
+    updateLayoutIgnorePendingStylesheets();

[ymalik, 2016/03/18 13:30:57]

@bokan, I am not sure whether we need to call
updateLayoutIgnorePendingStylesheets(). I think it makes sense and I see it
being called from Element::scrollLeft and friends. WDYT?

[bokan, 2016/03/18 16:05:07]

I think we need it. The reason being that the visual viewport's scroll position
depends on the size of the layout viewport. The layout viewport's size depends
on the layout since it's calculated based on the minimum possible page scale and
the minimum page scale depends on content width. This means that a really wide
element can increase/decrease the layout viewport's width which means the max
scroll position will change.

[ymalik, 2016/03/22 16:35:06]

Acknowledged.

+
+    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())
@@ -226,6 +290,13 @@ void VisualViewport::setScaleAndLocation(float scale, const FloatPoint& location
     if (!valuesChanged)
         return;
 
+    if (RuntimeEnabledFeatures::visualViewportAPIEnabled()) {
+        if (Document* document = mainFrame()->document()) {
+            if (document->documentElement())
+                document->documentElement()->dispatchViewportChangedEvent();
+        }
+    }
+
     InspectorInstrumentation::didUpdateLayout(mainFrame());
     mainFrame()->loader().saveScrollState();