Remove HTMLLinkElement.scope_

This member variable was introduced for Service Worker link registration
by https://codereview.chromium.org/1781783002.
Service Worker link registration was removed from the specification.
And the logic was removed by http://crrev.com/c/792731.
So this variable is not used anymore.

Bug: 788604
Change-Id: Ieaf4f3cb31526d9767f4a6666f2c26a1109d0605
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2622357Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Auto-Submit: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842382}

third_party/blink/renderer/core/html/html_link_element.cc

@@ -134,9 +134,6 @@ void HTMLLinkElement::ParseAttribute(
   } else if (name == html_names::kMediaAttr) {
     media_ = value.LowerASCII();
     Process();
-  } else if (name == html_names::kScopeAttr) {
-    scope_ = value;
-    Process();
   } else if (name == html_names::kIntegrityAttr) {
     integrity_ = value;
   } else if (name == html_names::kImportanceAttr &&

third_party/blink/renderer/core/html/html_link_element.h

@@ -69,7 +69,6 @@ class CORE_EXPORT HTMLLinkElement final : public HTMLElement,
   DOMTokenList& relList() const {
     return static_cast<DOMTokenList&>(*rel_list_);
   }
-  String Scope() const { return scope_; }
 
   const AtomicString& GetType() const;
 
@@ -177,7 +176,6 @@ class CORE_EXPORT HTMLLinkElement final : public HTMLElement,
   Vector<gfx::Size> icon_sizes_;
   Member<RelList> rel_list_;
   LinkRelAttribute rel_attribute_;
-  String scope_;
   Member<DOMTokenList> resources_;
   HashSet<KURL> valid_resource_urls_;