Bug 1147279 - Get correct translation when layer optimize away. r=roc

--HG--
extra : rebase_source : e9e56fe3a0f1d8a88de1e0b40151ed2e452e4ff9

gfx/layers/LayersTypes.h

@@ -213,6 +213,21 @@ struct EventRegions {
     mDispatchToContentHitRegion.Sub(aMinuend.mDispatchToContentHitRegion, aSubtrahend);
   }
 
+  void ApplyTranslationAndScale(float aXTrans, float aYTrans, float aXScale, float aYScale)
+  {
+    mHitRegion.ScaleRoundOut(aXScale, aYScale);
+    mDispatchToContentHitRegion.ScaleRoundOut(aXScale, aYScale);
+    mNoActionRegion.ScaleRoundOut(aXScale, aYScale);
+    mHorizontalPanRegion.ScaleRoundOut(aXScale, aYScale);
+    mVerticalPanRegion.ScaleRoundOut(aXScale, aYScale);
+
+    mHitRegion.MoveBy(aXTrans, aYTrans);
+    mDispatchToContentHitRegion.MoveBy(aXTrans, aYTrans);
+    mNoActionRegion.MoveBy(aXTrans, aYTrans);
+    mHorizontalPanRegion.MoveBy(aXTrans, aYTrans);
+    mVerticalPanRegion.MoveBy(aXTrans, aYTrans);
+  }
+
   void Transform(const gfx3DMatrix& aTransform)
   {
     mHitRegion.Transform(aTransform);

gfx/src/nsRegion.cpp

@@ -565,6 +565,11 @@ uint64_t nsRegion::Area () const
 
 nsRegion& nsRegion::ScaleRoundOut (float aXScale, float aYScale)
 {
+  if (mozilla::gfx::FuzzyEqual(aXScale, 1.0f) &&
+      mozilla::gfx::FuzzyEqual(aYScale, 1.0f)) {
+    return *this;
+  }
+
   int n;
   pixman_box32_t *boxes = pixman_region32_rectangles(&mImpl, &n);
   for (int i=0; i<n; i++) {

layout/base/FrameLayerBuilder.cpp

@@ -3034,12 +3034,9 @@ void ContainerState::FinishPaintedLayerData(PaintedLayerData& aData, FindOpaqueB
         ScaleRegionToOutsidePixels(data->mDispatchToContentHitRegion));
     regions.mHitRegion.OrWith(maybeHitRegion);
 
-    nsIntPoint translation = -GetTranslationForPaintedLayer(data->mLayer);
-    regions.mHitRegion.MoveBy(translation);
-    regions.mDispatchToContentHitRegion.MoveBy(translation);
-    regions.mNoActionRegion.MoveBy(translation);
-    regions.mHorizontalPanRegion.MoveBy(translation);
-    regions.mVerticalPanRegion.MoveBy(translation);
+    Matrix mat = layer->GetBaseTransform().As2D();
+    mat.Invert();
+    regions.ApplyTranslationAndScale(mat._31, mat._32, mat._11, mat._22);
 
     layer->SetEventRegions(regions);
   }