Made top controls work with virtual viewport pinch-to-zoom. (Blink)

Source/core/frame/PinchViewport.cpp

Index: Source/core/frame/PinchViewport.cpp
diff --git a/Source/core/frame/PinchViewport.cpp b/Source/core/frame/PinchViewport.cpp
index 3c877332714d5e26b104395b96ea3ed1bfde8e5f..4f09afc5975ba1a7f426113b5469dd595bccccb9 100644
--- a/Source/core/frame/PinchViewport.cpp
+++ b/Source/core/frame/PinchViewport.cpp
@@ -67,6 +67,7 @@ namespace blink {
 PinchViewport::PinchViewport(FrameHost& owner)
     : m_frameHost(owner)
     , m_scale(1)
+    , m_topControlsAdjustment(0)
 {
     reset();
 }
@@ -81,8 +82,6 @@ void PinchViewport::setSize(const IntSize& size)
     TRACE_EVENT2("blink", "PinchViewport::setSize", "width", size.width(), "height", size.height());
     m_size = size;
 
-    clampToBoundaries();
-
     if (m_innerViewportContainerLayer) {
         m_innerViewportContainerLayer->setSize(m_size);
 
@@ -111,6 +110,7 @@ void PinchViewport::mainFrameDidChangeSize()
 FloatRect PinchViewport::visibleRect() const
 {
     FloatSize scaledSize(m_size);
+    scaledSize.expand(0, m_topControlsAdjustment);
     scaledSize.scale(1 / m_scale);
     return FloatRect(m_offset, scaledSize);
 }
@@ -356,7 +356,24 @@ IntPoint PinchViewport::minimumScrollPosition() const
 
 IntPoint PinchViewport::maximumScrollPosition() const
 {
-    return flooredIntPoint(FloatSize(contentsSize()) - visibleRect().size());
+    FloatSize frameViewSize(contentsSize());
+
+    if (m_topControlsAdjustment) {

[aelias_OOO_until_Jul13, 2014/10/09 22:58:53]

Please remove this if() statement, it's unnecessary complexity since it doesn't
change the behavior.  Maybe replace it with a comment explaining you expect this
will have an effect in the top controls case.

[bokan, 2014/10/09 23:22:49]

Done.

[bokan, 2014/10/10 14:39:56]

Actually, the 'if' is needed, there are cases where the aspect ratios don't
match. The CrOS OSK is the one real world example. That's by design since we
don't want the fixed pos elements to move when the keyboard comes up.

+        float aspectRatio = visibleRect().width() / visibleRect().height();
+        float adjustment = frameViewSize.width() / aspectRatio - frameViewSize.height();
+        frameViewSize.expand(0, adjustment);
+    }
+
+    frameViewSize.scale(m_scale);
+    frameViewSize = flooredIntSize(frameViewSize);
+
+    FloatSize viewportSize(m_size);
+    viewportSize.expand(0, m_topControlsAdjustment);
+
+    FloatSize maxPosition = frameViewSize - viewportSize;
+    maxPosition.scale(1 / m_scale);
+
+    return flooredIntPoint(maxPosition);
 }
 
 IntPoint PinchViewport::clampDocumentOffsetAtScale(const IntPoint& offset, float scale)
@@ -379,6 +396,11 @@ IntPoint PinchViewport::clampDocumentOffsetAtScale(const IntPoint& offset, float
     return clamped;
 }
 
+void PinchViewport::setTopControlsAdjustment(float adjustment)
+{
+    m_topControlsAdjustment = adjustment;
+}
+
 IntRect PinchViewport::scrollableAreaBoundingBox() const
 {
     // This method should return the bounding box in the parent view's coordinate