Implement margin for fixed elements.

Last missing piece to fix Bug:2252505

Billmonk.com uses a centered fixed element with negative margins,
and we were not accounting for those...
Accounting for the margins move the fixed layer at the same place
than webkit think it is, and therefore clicks do work.

Change-Id: I6a736d06273df7d2bbc597c17ce042aa8b75b4e2

3 files changed, 34 insertions, 5 deletions

diff --git a/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp b/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
index 93469b0..7b479bf 100644
--- a/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/GraphicsLayerAndroid.cpp
@@ -241,7 +241,16 @@ void GraphicsLayerAndroid::updateFixedPosition()
         int w = view->rightVisibleOverflow() - view->leftVisibleOverflow();
         int h = view->bottomVisibleOverflow() - view->topVisibleOverflow();
 
-        m_contentLayer->setFixedPosition(left, top, right, bottom, w, h);
+        SkLength marginLeft, marginTop, marginRight, marginBottom;
+        marginLeft = convertLength(view->style()->marginLeft());
+        marginTop = convertLength(view->style()->marginTop());
+        marginRight = convertLength(view->style()->marginRight());
+        marginBottom = convertLength(view->style()->marginBottom());
+
+        m_contentLayer->setFixedPosition(left, top, right, bottom,
+                                         marginLeft, marginTop,
+                                         marginRight, marginBottom,
+                                         w, h);
     }
 }
 
diff --git a/WebCore/platform/graphics/android/LayerAndroid.cpp b/WebCore/platform/graphics/android/LayerAndroid.cpp
index 3b1743d..bfb086c 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.cpp
+++ b/WebCore/platform/graphics/android/LayerAndroid.cpp
@@ -79,6 +79,10 @@ LayerAndroid::LayerAndroid(const LayerAndroid& layer) : SkLayer(layer),
     m_fixedTop = layer.m_fixedTop;
     m_fixedRight = layer.m_fixedRight;
     m_fixedBottom = layer.m_fixedBottom;
+    m_fixedMarginLeft = layer.m_fixedMarginLeft;
+    m_fixedMarginTop = layer.m_fixedMarginTop;
+    m_fixedMarginRight = layer.m_fixedMarginRight;
+    m_fixedMarginBottom = layer.m_fixedMarginBottom;
     m_fixedWidth = layer.m_fixedWidth;
     m_fixedHeight = layer.m_fixedHeight;
 
@@ -256,14 +260,14 @@ void LayerAndroid::updateFixedLayersPositions(const SkRect& viewport)
         float y = dy;
 
         if (m_fixedLeft.defined())
-            x += m_fixedLeft.calcFloatValue(w);
+            x += m_fixedMarginLeft.calcFloatValue(w) + m_fixedLeft.calcFloatValue(w);
         else if (m_fixedRight.defined())
-            x += w - m_fixedRight.calcFloatValue(w) - m_fixedWidth;
+            x += w - m_fixedMarginRight.calcFloatValue(w) - m_fixedRight.calcFloatValue(w) - m_fixedWidth;
 
         if (m_fixedTop.defined())
-            y += m_fixedTop.calcFloatValue(h);
+            y += m_fixedMarginTop.calcFloatValue(h) + m_fixedTop.calcFloatValue(h);
         else if (m_fixedBottom.defined())
-            y += h - m_fixedBottom.calcFloatValue(h) - m_fixedHeight;
+            y += h - m_fixedMarginBottom.calcFloatValue(h) - m_fixedBottom.calcFloatValue(h) - m_fixedHeight;
 
         this->setPosition(x, y);
     }
@@ -492,6 +496,10 @@ void LayerAndroid::dumpLayers(FILE* file, int indentLevel) const
     writeLength(file, indentLevel + 1, "fixedTop", m_fixedTop);
     writeLength(file, indentLevel + 1, "fixedRight", m_fixedRight);
     writeLength(file, indentLevel + 1, "fixedBottom", m_fixedBottom);
+    writeLength(file, indentLevel + 1, "fixedMarginLeft", m_fixedMarginLeft);
+    writeLength(file, indentLevel + 1, "fixedMarginTop", m_fixedMarginTop);
+    writeLength(file, indentLevel + 1, "fixedMarginRight", m_fixedMarginRight);
+    writeLength(file, indentLevel + 1, "fixedMarginBottom", m_fixedMarginBottom);
     writeIntVal(file, indentLevel + 1, "fixedWidth", m_fixedWidth);
     writeIntVal(file, indentLevel + 1, "fixedHeight", m_fixedHeight);
 
diff --git a/WebCore/platform/graphics/android/LayerAndroid.h b/WebCore/platform/graphics/android/LayerAndroid.h
index 247e902..b92f4ac 100644
--- a/WebCore/platform/graphics/android/LayerAndroid.h
+++ b/WebCore/platform/graphics/android/LayerAndroid.h
@@ -92,12 +92,20 @@ public:
                           SkLength top,    // CSS top property
                           SkLength right,  // CSS right property
                           SkLength bottom, // CSS bottom property
+                          SkLength marginLeft,   // CSS margin-left property
+                          SkLength marginTop,    // CSS margin-top property
+                          SkLength marginRight,  // CSS margin-right property
+                          SkLength marginBottom, // CSS margin-bottom property
                           int width,       // visible overflow width
                           int height) {    // visible overflow height
         m_fixedLeft = left;
         m_fixedTop = top;
         m_fixedRight = right;
         m_fixedBottom = bottom;
+        m_fixedMarginLeft = marginLeft;
+        m_fixedMarginTop = marginTop;
+        m_fixedMarginRight = marginRight;
+        m_fixedMarginBottom = marginBottom;
         m_fixedWidth = width;
         m_fixedHeight = height;
         m_isFixed = true;
@@ -173,6 +181,10 @@ private:
     SkLength m_fixedTop;
     SkLength m_fixedRight;
     SkLength m_fixedBottom;
+    SkLength m_fixedMarginLeft;
+    SkLength m_fixedMarginTop;
+    SkLength m_fixedMarginRight;
+    SkLength m_fixedMarginBottom;
     int m_fixedWidth;
     int m_fixedHeight;