Fix click issues when using fixed elements. This CL also fix the positioning

of a fixed layer when no position is defined, and also only use the screen
to position only the fixed elements, not other types of positioned elements.

Bug:2521087

The click issues were due to not returning the fixed element when looking
for a parent stackingContext in RenderLayer::stackingContext().
This resulted in incorrect coordinates for the layers children of a
fixed layer, that we then had to recompute in
RenderLayer::convertToLayerCoords(), but this in turns was invaliding
hit test detection...

Fixed elements are now positioned relative to the screen instead of the
virtual viewport (ANDROID_FIXED_ELEMENTS); but this was applying
indiscriminantly to all positioned elements, absolute elements included.
The CL modify RenderBox::containingBlockWidthForPositioned() and
RenderBox::containingBlockHeightForPositioned() to only do this for
fixed elements.

Finally, fixed layers were wrongly positioned if the positions were not
fully set (e.g. only setting top:0 but no left or right). The change to
LayerAndroid::updateFixedLayersPositions() fixes this.

Change-Id: I07a179dd631a2bc1a313e33ffcf69ef388ecb7ca

1 files changed, 8 insertions, 8 deletions

diff --git a/WebCore/platform/graphics/android/LayerAndroid.cpp b/WebCore/platform/graphics/android/LayerAndroid.cpp
index c17a034..3b1743d 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/LayerAndroid.cpp
@@ -245,25 +245,25 @@ const LayerAndroid* LayerAndroid::find(int x, int y) const
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void LayerAndroid::updateFixedLayersPositions(const SkRect& viewport) {
-
+void LayerAndroid::updateFixedLayersPositions(const SkRect& viewport)
+{
     if (m_isFixed) {
-        float x = 0;
-        float y = 0;
         float w = viewport.width();
         float h = viewport.height();
         float dx = viewport.fLeft;
         float dy = viewport.fTop;
+        float x = dx;
+        float y = dy;
 
         if (m_fixedLeft.defined())
-            x = dx + m_fixedLeft.calcFloatValue(w);
+            x += m_fixedLeft.calcFloatValue(w);
         else if (m_fixedRight.defined())
-            x = dx + w - m_fixedRight.calcFloatValue(w) - m_fixedWidth;
+            x += w - m_fixedRight.calcFloatValue(w) - m_fixedWidth;
 
         if (m_fixedTop.defined())
-            y = dy + m_fixedTop.calcFloatValue(h);
+            y += m_fixedTop.calcFloatValue(h);
         else if (m_fixedBottom.defined())
-            y = dy + h - m_fixedBottom.calcFloatValue(h) - m_fixedHeight;
+            y += h - m_fixedBottom.calcFloatValue(h) - m_fixedHeight;
 
         this->setPosition(x, y);
     }