Adjust DOMWindow properties to emulate old style pinch semantics

Source/core/frame/LocalDOMWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1134 matching lines @@
 
 int LocalDOMWindow::innerHeight() const
 {
     if (!frame())
         return 0;
 
     FrameView* view = frame()->view();
     if (!view)
         return 0;
 
+    FrameHost* host = frame()->host();
+    if (!host)
+        return 0;
+
     // FIXME: This is potentially too much work. We really only need to know the dimensions of the parent frame's renderer.
     if (Frame* parent = frame()->tree().parent()) {
         if (parent && parent->isLocalFrame())
             toLocalFrame(parent)->document()->updateLayoutIgnorePendingStylesheets();
     }
 
-    return adjustForAbsoluteZoom(view->visibleContentRect(IncludeScrollbars).height(), frame()->pageZoomFactor());
+    FloatSize viewportSize = host->settings().pinchVirtualViewportEnabled() && frame()->isMainFrame()
+        ? host->pinchViewport().visibleRect().size()
+        : view->visibleContentRect(IncludeScrollbars).size();
+
+    return adjustForAbsoluteZoom(expandedIntSize(viewportSize).height(), frame()->pageZoomFactor());
 }
 
 int LocalDOMWindow::innerWidth() const
 {
     if (!frame())
         return 0;
 
     FrameView* view = frame()->view();
     if (!view)
         return 0;
 
+    FrameHost* host = frame()->host();
+    if (!host)
+        return 0;
+
     // FIXME: This is potentially too much work. We really only need to know the dimensions of the parent frame's renderer.
     if (Frame* parent = frame()->tree().parent()) {
         if (parent && parent->isLocalFrame())
             toLocalFrame(parent)->document()->updateLayoutIgnorePendingStylesheets();
     }
 
-    return adjustForAbsoluteZoom(view->visibleContentRect(IncludeScrollbars).width(), frame()->pageZoomFactor());
+    FloatSize viewportSize = host->settings().pinchVirtualViewportEnabled() && frame()->isMainFrame()
+        ? host->pinchViewport().visibleRect().size()
+        : view->visibleContentRect(IncludeScrollbars).size();
+
+    return adjustForAbsoluteZoom(expandedIntSize(viewportSize).width(), frame()->pageZoomFactor());
 }
 
 int LocalDOMWindow::screenX() const
 {
     if (!frame())
         return 0;
 
     FrameHost* host = frame()->host();
     if (!host)
         return 0;
@@ skipping 19 matching lines @@
 
 double LocalDOMWindow::scrollX() const
 {
     if (!frame())
         return 0;
 
     FrameView* view = frame()->view();
     if (!view)
         return 0;
 
+    FrameHost* host = frame()->host();
+    if (!host)
+        return 0;
+
     frame()->document()->updateLayoutIgnorePendingStylesheets();
 
-    return adjustScrollForAbsoluteZoom(view->scrollX(), frame()->pageZoomFactor());
+    double viewportX = view->scrollX();
+
+    if (host->settings().pinchVirtualViewportEnabled() && frame()->isMainFrame())
+        viewportX += host->pinchViewport().location().x();
+
+    return adjustScrollForAbsoluteZoom(viewportX, frame()->pageZoomFactor());
 }
 
 double LocalDOMWindow::scrollY() const
 {
     if (!frame())
         return 0;
 
     FrameView* view = frame()->view();
     if (!view)
         return 0;
 
+    FrameHost* host = frame()->host();
+    if (!host)
+        return 0;
+
     frame()->document()->updateLayoutIgnorePendingStylesheets();
 
-    return adjustScrollForAbsoluteZoom(view->scrollY(), frame()->pageZoomFactor());
+    double viewportY = view->scrollY();
+
+    if (host->settings().pinchVirtualViewportEnabled() && frame()->isMainFrame())
+        viewportY += host->pinchViewport().location().y();
+
+    return adjustScrollForAbsoluteZoom(viewportY, frame()->pageZoomFactor());
 }
 
 bool LocalDOMWindow::closed() const
 {
     return !frame() || !frame()->host();
 }
 
 unsigned LocalDOMWindow::length() const
 {
     if (!isCurrentlyDisplayedInFrame())
@@ skipping 144 matching lines @@
         return true;
     }
 
     if (ScrollableArea::scrollBehaviorFromString(scrollOptions.behavior(), scrollBehavior))
         return true;
 
     exceptionState.throwTypeError("The ScrollBehavior provided is invalid.");
     return false;
 }
 
+static void scrollViewportTo(LocalFrame* frame, DoublePoint offset, ScrollBehavior scrollBehavior)
+{
+    FrameView* view = frame->view();
+    if (!view)
+        return;
+
+    FrameHost* host = frame->host();
+    if (!host)
+        return;
+
+    view->setScrollPosition(offset, scrollBehavior);
+
+    if (host->settings().pinchVirtualViewportEnabled() && frame->isMainFrame()) {
+        PinchViewport& pinchViewport = frame->host()->pinchViewport();
+        DoubleSize excessDelta = offset - DoublePoint(pinchViewport.visibleRectInDocument().location());
+        pinchViewport.move(FloatPoint(excessDelta.width(), excessDelta.height()));

[Rick Byers, 2014/11/18 20:53:31]

How does this interact with smooth scrolling?  It looks like PinchViewport
doesn't have a way to honor ScrollBehavior "smooth" if that's what was
requested.  This is a behavior change compared to the old viewport path, right?

I'm OK treating that as an orthogonal issue, but please file a bug for it and
add a FIXME referencing that bug here.

[bokan, 2014/11/18 23:21:50]

This is a change, though is ScrollBehavior gone live yet? Nothing on the web
mentions it so I think maybe it's still behind a flag?
Done. crbug.com/434497

[Rick Byers, 2014/11/20 19:23:31]

Oh right, it is.  CSSOMSmoothScroll is still marked experimental.
Thanks.  I've blocked ajuma's smooth scroll bug on this.

+    }
+}
+
 void LocalDOMWindow::scrollBy(double x, double y, ScrollBehavior scrollBehavior) const
 {
     if (!isCurrentlyDisplayedInFrame())
         return;
 
     document()->updateLayoutIgnorePendingStylesheets();
 
     FrameView* view = frame()->view();
     if (!view)
         return;
 
+    FrameHost* host = frame()->host();
+    if (!host)
+        return;
+
     if (std::isnan(x) || std::isnan(y))
         return;
 
+    DoublePoint currentOffset = host->settings().pinchVirtualViewportEnabled() && frame()->isMainFrame()
+        ? DoublePoint(host->pinchViewport().visibleRectInDocument().location())
+        : view->scrollPositionDouble();
+
     DoubleSize scaledOffset(x * frame()->pageZoomFactor(), y * frame()->pageZoomFactor());
-    view->scrollBy(scaledOffset, scrollBehavior);

[Rick Byers, 2014/11/18 20:53:31]

There are a couple other places in the code that call FrameView::scrollBy. 
Should any of them be updated to use this logic too to preserve behavior? 
Perhaps this logic really belongs in FrameView instead of LocalDOMWidow (seems
similar to FrameView::scrollElementToRect)?

[bokan, 2014/11/18 23:21:50]

Technically yes, but they're only used from SpacialNavigation and PanScrolling
so I don't think they apply to Android. This patch will need to get merged so I
don't want to touch anything I don't have to. This logic doesn't really belong
in FrameView either and I have bugs to remove it from there as well so I'd
rather leave it here for now. I've added a FIXME here referencing the bug to
remove dependencies on PinchViewport (crbug.com/371896).

[Rick Byers, 2014/11/20 19:23:30]

SGTM, thanks.

+    scrollViewportTo(frame(), currentOffset + scaledOffset, scrollBehavior);
 }
 
 void LocalDOMWindow::scrollBy(double x, double y, const ScrollOptions& scrollOptions, ExceptionState &exceptionState) const
 {
     ScrollBehavior scrollBehavior = ScrollBehaviorAuto;
     if (!scrollBehaviorFromScrollOptions(scrollOptions, scrollBehavior, exceptionState))
         return;
     scrollBy(x, y, scrollBehavior);
 }
 
 void LocalDOMWindow::scrollTo(double x, double y, ScrollBehavior scrollBehavior) const
 {
     if (!isCurrentlyDisplayedInFrame())
         return;
 
     document()->updateLayoutIgnorePendingStylesheets();
 
-    RefPtrWillBeRawPtr<FrameView> view = frame()->view();
-    if (!view)
-        return;
-
     if (std::isnan(x) || std::isnan(y))
         return;
 
     DoublePoint layoutPos(x * frame()->pageZoomFactor(), y * frame()->pageZoomFactor());
-    view->setScrollPosition(layoutPos, scrollBehavior);
+    scrollViewportTo(frame(), layoutPos, scrollBehavior);
 }
 
 void LocalDOMWindow::scrollTo(double x, double y, const ScrollOptions& scrollOptions, ExceptionState& exceptionState) const
 {
     ScrollBehavior scrollBehavior = ScrollBehaviorAuto;
     if (!scrollBehaviorFromScrollOptions(scrollOptions, scrollBehavior, exceptionState))
         return;
     scrollTo(x, y, scrollBehavior);
 }
 
@@ skipping 507 matching lines @@
     return m_frameObserver->frame();
 }
 
 v8::Handle<v8::Object> LocalDOMWindow::wrap(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
 {
     ASSERT_NOT_REACHED(); // LocalDOMWindow has [Custom=ToV8].
     return v8::Handle<v8::Object>();
 }
 
 } // namespace blink