Mark GURL-producing methods as nodiscard

Change-Id: I84d1f59eb01ad15ca4837d7718c46a445fd2e5ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5953898
Commit-Queue: Charlie Harrison <csharrison@chromium.org>
Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Auto-Submit: Chris Fredrickson <cfredric@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1373697}

url/gurl.h

@@ -159,8 +159,8 @@ class COMPONENT_EXPORT(URL) GURL {
   //
   // It is an error to resolve a URL relative to an invalid URL. The result
   // will be the empty URL.
-  GURL Resolve(std::string_view relative) const;
+  [[nodiscard]] GURL Resolve(std::string_view relative) const;
-  GURL Resolve(std::u16string_view relative) const;
+  [[nodiscard]] GURL Resolve(std::u16string_view relative) const;
 
   // Creates a new GURL by replacing the current URL's components with the
   // supplied versions. See the Replacements class in url_canon.h for more.
@@ -185,7 +185,7 @@ class COMPONENT_EXPORT(URL) GURL {
   //
   // It is an error to get an empty path on an invalid URL. The result
   // will be the empty URL.
-  GURL GetWithEmptyPath() const;
+  [[nodiscard]] GURL GetWithEmptyPath() const;
 
   // A helper function to return a GURL without the filename, query values, and
   // fragment. For example,
@@ -194,7 +194,7 @@ class COMPONENT_EXPORT(URL) GURL {
   // GURL("https://www.foo.com/bar/").GetWithoutFilename().spec()
   // will return "https://www.foo.com/bar/". If the GURL is invalid or missing a
   // scheme, authority or path, it will return an empty, invalid GURL.
-  GURL GetWithoutFilename() const;
+  [[nodiscard]] GURL GetWithoutFilename() const;
 
   // A helper function to return a GURL without the Ref (also named Fragment
   // Identifier). For example,
@@ -202,7 +202,7 @@ class COMPONENT_EXPORT(URL) GURL {
   // will return "https://www.foo.com/index.html".
   // If the GURL is invalid or missing a
   // scheme, authority or path, it will return an empty, invalid GURL.
-  GURL GetWithoutRef() const;
+  [[nodiscard]] GURL GetWithoutRef() const;
 
   // A helper function to return a GURL containing just the scheme, host,
   // and port from a URL. Equivalent to clearing any username and password,
@@ -219,13 +219,13 @@ class COMPONENT_EXPORT(URL) GURL {
   // conversions will likely return a wrong result for about:blank and/or
   // in the presence of iframe.sandbox attribute. Prefer to get origins directly
   // from the source (e.g. RenderFrameHost::GetLastCommittedOrigin).
-  GURL DeprecatedGetOriginAsURL() const;
+  [[nodiscard]] GURL DeprecatedGetOriginAsURL() const;
 
   // A helper function to return a GURL stripped from the elements that are not
   // supposed to be sent as HTTP referrer: username, password and ref fragment.
   // For invalid URLs or URLs that no valid referrers, an empty URL will be
   // returned.
-  GURL GetAsReferrer() const;
+  [[nodiscard]] GURL GetAsReferrer() const;
 
   // Returns true if the scheme for the current URL is a known "standard-format"
   // scheme. A standard-format scheme adheres to what RFC 3986 calls "generic

url/gurl_fuzzer.cc

@@ -81,13 +81,13 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
     CheckIdempotency(url_from_string_piece_part);
     CheckReplaceComponentsPreservesSpec(url_from_string_piece_part);
 
-    url_from_string_piece_part.Resolve(relative_string);
+    std::ignore = url_from_string_piece_part.Resolve(relative_string);
 
     if (relative_size % sizeof(char16_t) == 0) {
       std::u16string relative_string16(
           reinterpret_cast<const char16_t*>(data + size_t_bytes),
           relative_size / sizeof(char16_t));
-      url_from_string_piece_part.Resolve(relative_string16);
+      std::ignore = url_from_string_piece_part.Resolve(relative_string16);
     }
   }
   return 0;