Expand base layer bounds to fill viewport

Additionally, paint area outside the content bounds with content bg color in
software rendering path.

bug:6304213

Change-Id: I6fe5246e82d30fe000e570c8dccb605d46fc428d

2 files changed, 15 insertions, 0 deletions

diff --git a/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.cpp b/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.cpp
index 1de5ae7..ce520b4 100644
--- a/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.cpp
+++ b/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.cpp
@@ -53,4 +53,17 @@ void BaseLayerAndroid::getLocalTransform(SkMatrix* matrix) const
     matrix->preConcat(getMatrix());
 }
 
+IFrameLayerAndroid* BaseLayerAndroid::updatePosition(SkRect viewport,
+                                                     IFrameLayerAndroid* parentIframeLayer)
+{
+    if (viewport.fRight > getWidth() || viewport.fBottom > getHeight()) {
+        // To handle the viewport expanding past the layer's size with HW accel,
+        // expand the size of the layer, so that tiles will cover the viewport.
+        setSize(std::max(viewport.fRight, getWidth()),
+                std::max(viewport.fBottom, getHeight()));
+    }
+
+    return LayerAndroid::updatePosition(viewport, parentIframeLayer);
+}
+
 } // namespace WebCore
diff --git a/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.h b/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.h
index 0ef39c8..f4cf9f3 100644
--- a/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.h
+++ b/Source/WebCore/platform/graphics/android/layers/BaseLayerAndroid.h
@@ -49,6 +49,8 @@ public:
     virtual void getLocalTransform(SkMatrix* matrix) const;
     virtual const TransformationMatrix* drawTransform() const { return 0; }
 
+    virtual IFrameLayerAndroid* updatePosition(SkRect viewport,
+                                               IFrameLayerAndroid* parentIframeLayer);
 private:
     // TODO: move to SurfaceCollection.
     Color m_color;