Revert "Neuter the "screen scale factor" computation for SVG <text>"

third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp

Index: third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp b/third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp
index 1811efaa92538549f59d1b44e7d9e8497b5bc6d9..25b768fa770307f9c5c3c5c72f2353e3ddbb3212 100644
--- a/third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp
@@ -37,6 +37,7 @@
 #include "core/layout/svg/LayoutSVGViewportContainer.h"
 #include "core/layout/svg/SVGResources.h"
 #include "core/layout/svg/SVGResourcesCache.h"
+#include "core/page/Page.h"
 #include "core/paint/PaintLayer.h"
 #include "core/svg/SVGElement.h"
 #include "platform/geometry/TransformState.h"
@@ -519,7 +520,7 @@ SubtreeContentTransformScope::~SubtreeContentTransformScope() {
   m_savedContentTransformation.copyTransformTo(s_currentContentTransformation);
 }
 
-float SVGLayoutSupport::calculateScreenFontSizeScalingFactor(
+AffineTransform SVGLayoutSupport::deprecatedCalculateTransformToLayer(
     const LayoutObject* layoutObject) {
   AffineTransform transform;
   while (layoutObject) {
@@ -528,10 +529,43 @@ float SVGLayoutSupport::calculateScreenFontSizeScalingFactor(
       break;
     layoutObject = layoutObject->parent();
   }
-  transform.multiply(
-      SubtreeContentTransformScope::currentContentTransformation());
-  return clampTo<float>(
-      sqrt((transform.xScaleSquared() + transform.yScaleSquared()) / 2));
+
+  // Continue walking up the layer tree, accumulating CSS transforms.
+  // FIXME: this queries layer compositing state - which is not
+  // supported during layout. Hence, the result may not include all CSS
+  // transforms.
+  PaintLayer* layer = layoutObject ? layoutObject->enclosingLayer() : 0;
+  while (layer && layer->isAllowedToQueryCompositingState()) {
+    // We can stop at compositing layers, to match the backing resolution.
+    // FIXME: should we be computing the transform to the nearest composited
+    // layer, or the nearest composited layer that does not paint into its
+    // ancestor? I think this is the nearest composited ancestor since we will
+    // inherit its transforms in the composited layer tree.
+    if (layer->compositingState() != NotComposited)
+      break;
+
+    if (TransformationMatrix* layerTransform = layer->transform())
+      transform = layerTransform->toAffineTransform() * transform;
+
+    layer = layer->parent();
+  }
+
+  return transform;
+}
+
+float SVGLayoutSupport::calculateScreenFontSizeScalingFactor(
+    const LayoutObject* layoutObject) {
+  DCHECK(layoutObject);
+
+  // FIXME: trying to compute a device space transform at record time is wrong.
+  // All clients should be updated to avoid relying on this information, and the
+  // method should be removed.
+  AffineTransform ctm =
+      deprecatedCalculateTransformToLayer(layoutObject) *
+      SubtreeContentTransformScope::currentContentTransformation();
+  ctm.scale(layoutObject->document().page()->deviceScaleFactorDeprecated());
+
+  return clampTo<float>(sqrt((ctm.xScaleSquared() + ctm.yScaleSquared()) / 2));
 }
 
 static inline bool compareCandidateDistance(const SearchCandidate& r1,