Use HashSet to store URLs in a <link> element's resource attribute

This CL is factored out of https://crrev.com/c/2266237 so that we can
land this separately.

BUG: 1082020
Change-Id: I6967bdfb0f0f2680f4d5f5f390f3140f31ea2826
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2266135Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Hayato Ito <hayato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782779}

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

@@ -153,11 +153,12 @@ void HTMLLinkElement::ParseAttribute(
     // Parse the attribute value as a space-separated list of urls
     SpaceSplitString urls(value);
     valid_resource_urls_.clear();
-    valid_resource_urls_.ReserveCapacity(SafeCast<wtf_size_t>(urls.size()));
+    valid_resource_urls_.ReserveCapacityForSize(
+        SafeCast<wtf_size_t>(urls.size()));
     for (wtf_size_t i = 0; i < urls.size(); ++i) {
       KURL url = LinkWebBundle::ParseResourceUrl(urls[i]);
       if (url.IsValid()) {
-        valid_resource_urls_.push_back(std::move(url));
+        valid_resource_urls_.insert(std::move(url));
       }
     }
     Process();

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

@@ -38,6 +38,7 @@
 #include "third_party/blink/renderer/core/html/rel_list.h"
 #include "third_party/blink/renderer/core/loader/link_loader_client.h"
 #include "third_party/blink/renderer/platform/loader/fetch/fetch_parameters.h"
+#include "third_party/blink/renderer/platform/wtf/hash_set.h"
 
 namespace blink {
 
@@ -100,7 +101,9 @@ class CORE_EXPORT HTMLLinkElement final : public HTMLElement,
   // IDL method.
   DOMTokenList* resources() const;
 
-  const Vector<KURL>& ValidResourceUrls() const { return valid_resource_urls_; }
+  const HashSet<KURL>& ValidResourceUrls() const {
+    return valid_resource_urls_;
+  }
 
   void ScheduleEvent();
 
@@ -181,8 +184,7 @@ class CORE_EXPORT HTMLLinkElement final : public HTMLElement,
   LinkRelAttribute rel_attribute_;
   String scope_;
   Member<DOMTokenList> resources_;
-  // TODO(hayato): It might be better to use HashMap. Re-think later.
-  Vector<KURL> valid_resource_urls_;
+  HashSet<KURL> valid_resource_urls_;
 
   bool created_by_parser_;
 };

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

@@ -41,7 +41,8 @@ TEST(LinkWebBundleTest, ResourcesAttribute) {
   link->setAttribute(html_names::kResourcesAttr, "https://test.example.com");
   EXPECT_EQ("https://test.example.com", resources->value());
   EXPECT_EQ(1u, link->ValidResourceUrls().size());
-  EXPECT_EQ(KURL("https://test.example.com"), link->ValidResourceUrls()[0]);
+  EXPECT_TRUE(
+      link->ValidResourceUrls().Contains(KURL("https://test.example.com")));
 
   // Invalid urls
   link->setAttribute(html_names::kResourcesAttr,
@@ -61,8 +62,10 @@ TEST(LinkWebBundleTest, ResourcesAttribute) {
   link->setAttribute(html_names::kResourcesAttr,
                      "https://test1.example.com https://test2.example.com");
   EXPECT_EQ(2u, link->ValidResourceUrls().size());
-  EXPECT_EQ(KURL("https://test1.example.com"), link->ValidResourceUrls()[0]);
-  EXPECT_EQ(KURL("https://test2.example.com"), link->ValidResourceUrls()[1]);
+  EXPECT_TRUE(
+      link->ValidResourceUrls().Contains(KURL("https://test1.example.com")));
+  EXPECT_TRUE(
+      link->ValidResourceUrls().Contains(KURL("https://test2.example.com")));
 
   // Space-separated valid and invalid urls
   link->setAttribute(html_names::kResourcesAttr,
@@ -73,8 +76,10 @@ TEST(LinkWebBundleTest, ResourcesAttribute) {
       "https://test2.example.com",
       resources->value());
   EXPECT_EQ(2u, link->ValidResourceUrls().size());
-  EXPECT_EQ(KURL("https://test1.example.com"), link->ValidResourceUrls()[0]);
-  EXPECT_EQ(KURL("https://test2.example.com"), link->ValidResourceUrls()[1]);
+  EXPECT_TRUE(
+      link->ValidResourceUrls().Contains(KURL("https://test1.example.com")));
+  EXPECT_TRUE(
+      link->ValidResourceUrls().Contains(KURL("https://test2.example.com")));
 }
 
 }  // namespace blink