Add console errors and usecounter when srcset candidates are dropped

Source/core/html/parser/HTMLSrcsetParser.h

Index: Source/core/html/parser/HTMLSrcsetParser.h
diff --git a/Source/core/html/parser/HTMLSrcsetParser.h b/Source/core/html/parser/HTMLSrcsetParser.h
index 2662a81fb3a3d724d42c6cadad8e3e4c8fae5108..00f13bd93fbb8a201752c359f0c923906dcb4968 100644
--- a/Source/core/html/parser/HTMLSrcsetParser.h
+++ b/Source/core/html/parser/HTMLSrcsetParser.h
@@ -36,6 +36,8 @@
 
 namespace blink {
 
+class Document;
+
 enum { UninitializedDescriptor = -1 };
 
 class DescriptorParsingResult {
@@ -129,9 +131,9 @@ private:
     OriginAttribute m_originAttribute;
 };
 
-ImageCandidate bestFitSourceForSrcsetAttribute(float deviceScaleFactor, float sourceSize, const String& srcsetAttribute);
+ImageCandidate bestFitSourceForSrcsetAttribute(float deviceScaleFactor, float sourceSize, const String& srcsetAttribute, Document* = nullptr);
 
-ImageCandidate bestFitSourceForImageAttributes(float deviceScaleFactor, float sourceSize, const String& srcAttribute, const String& srcsetAttribute);
+ImageCandidate bestFitSourceForImageAttributes(float deviceScaleFactor, float sourceSize, const String& srcAttribute, const String& srcsetAttribute, Document* = nullptr);
 
 String bestFitSourceForImageAttributes(float deviceScaleFactor, float sourceSize, const String& srcAttribute, ImageCandidate& srcsetImageCandidate);