Document how effective zoom relates to StyleImage sizing

third_party/WebKit/Source/core/svg/graphics/SVGImage.h

Index: third_party/WebKit/Source/core/svg/graphics/SVGImage.h
diff --git a/third_party/WebKit/Source/core/svg/graphics/SVGImage.h b/third_party/WebKit/Source/core/svg/graphics/SVGImage.h
index b2b816268376495082e0a58f844339d5ce12e5c8..a5d71c8e0901b0f49853ec3f2e8279d28f308c0f 100644
--- a/third_party/WebKit/Source/core/svg/graphics/SVGImage.h
+++ b/third_party/WebKit/Source/core/svg/graphics/SVGImage.h
@@ -77,7 +77,10 @@ public:
 
     void updateUseCounters(Document&) const;
 
-    FloatSize concreteObjectSize(const FloatSize&) const;
+    // The defaultObjectSize is assumed to be unzoomed, i.e. it should
+    // not have the effective zoom level applied. The returned size is
+    // thus also independent of current zoom level.
+    FloatSize concreteObjectSize(const FloatSize& defaultObjectSize) const;
 
     // DisplayItemClient methods.
     String debugName() const final { return "SVGImage"; }