Merge 125486 - [chromium] renderSurface in incorrect space if owning layer has empty but non-zero b…

Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 528 matching lines @@
     if (layer->fixedToContainerLayer()) {
         // Special case: this layer is a composited fixed-position layer; we need to
         // explicitly compensate for all ancestors' nonzero scrollDeltas to keep this layer
         // fixed correctly.
         combinedTransform = currentScrollCompensationMatrix * combinedTransform;
     }
 
     // The drawTransform that gets computed below is effectively the layer's drawTransform, unless
     // the layer itself creates a renderSurface. In that case, the renderSurface re-parents the transforms.
     WebTransformationMatrix drawTransform = combinedTransform;
+    // M[draw] = M[parent] * LT * Tr[anchor2center] * Tr[center2origin]
+    drawTransform.translate(-layer->bounds().width() / 2.0, -layer->bounds().height() / 2.0);
     if (!layer->contentBounds().isEmpty() && !layer->bounds().isEmpty()) {
-        // M[draw] = M[parent] * LT * Tr[anchor2center] * Tr[center2anchor]
-        drawTransform.translate(-layer->bounds().width() / 2.0, -layer->bounds().height() / 2.0);
-        // M[draw] = M[parent] * LT * Tr[anchor2origin] * S[content2layer]
+        // M[draw] = M[parent] * LT * Tr[anchor2origin] * S[layer2content]
         drawTransform.scaleNonUniform(layer->bounds().width() / static_cast<double>(layer->contentBounds().width()),
                                       layer->bounds().height() / static_cast<double>(layer->contentBounds().height()));
     }
 
     // layerScreenSpaceTransform represents the transform between root layer's "screen space" and local content space.
     WebTransformationMatrix layerScreenSpaceTransform = fullHierarchyMatrix;
     if (!layer->preserves3D())
         CCMathUtil::flattenTransformTo2d(layerScreenSpaceTransform);
     layerScreenSpaceTransform.multiply(drawTransform);
     layer->setScreenSpaceTransform(layerScreenSpaceTransform);
@@ skipping 386 matching lines @@
 
         foundLayer = currentLayer;
         break;
     }
 
     // This can potentially return 0, which means the viewportPoint did not successfully hit test any layers, not even the root layer.
     return foundLayer;
 }
 
 } // namespace WebCore