Convert remaining WARN_UNUSED_RESULT to [[nodiscard] in //chrome.

Bug: 1287045
Change-Id: Idec667fafec3ab721311c101c8f1e0b72e5621cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3401761
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#961630}

chrome/browser/ui/find_bar/find_bar_host_interactive_uitest.cc

@@ -49,11 +49,8 @@ class FindInPageInteractiveTest : public InProcessBrowserTest {
 
 }  // namespace
 
-// Specifying a prototype so that we can add the WARN_UNUSED_RESULT attribute.
 [[nodiscard]] bool FocusedOnPage(WebContents* web_contents,
-                                 std::string* result);
-
-bool FocusedOnPage(WebContents* web_contents, std::string* result) {
+                                 std::string* result) {
   return content::ExecuteScriptAndExtractString(
       web_contents,
       "window.domAutomationController.send(getFocusedElement());",

chrome/browser/ui/web_applications/web_app_controller_browsertest.h

@@ -64,8 +64,8 @@ class WebAppControllerBrowserTest : public InProcessBrowserTest {
 
   // Simulates a page navigating itself to an URL and waits for the
   // navigation.
-  WARN_UNUSED_RESULT bool NavigateInRenderer(content::WebContents* contents,
-                                             const GURL& url);
+  [[nodiscard]] bool NavigateInRenderer(content::WebContents* contents,
+                                        const GURL& url);
 
   // Returns whether the installable check passed.
   static bool NavigateAndAwaitInstallabilityCheck(Browser* browser,

chrome/utility/importer/ie_importer_win.cc

@@ -155,20 +155,11 @@ struct IEOrderBookmarkComparator {
 //   };
 // where each item_id should correspond to a favorites link file (*.url) in
 // the current folder.
-// gcc, in its infinite wisdom, only allows WARN_UNUSED_RESULT for prototypes.
-// Clang, to be compatible with gcc, warns if WARN_UNUSED_RESULT is used in a
-// non-gcc compatible manner (-Wgcc-compat). So even though gcc isn't used to
-// build on Windows, declare some prototypes anyway to satisfy Clang's gcc
-// compatibility warnings.
 [[nodiscard]] bool ParseFavoritesOrderBlob(
     const Importer* importer,
     const std::vector<uint8_t>& blob,
     const base::FilePath& path,
-    std::map<base::FilePath, uint32_t>* sort_index);
-bool ParseFavoritesOrderBlob(const Importer* importer,
-                             const std::vector<uint8_t>& blob,
-                             const base::FilePath& path,
-                             std::map<base::FilePath, uint32_t>* sort_index) {
+    std::map<base::FilePath, uint32_t>* sort_index) {
   static const int kItemCountOffset = 16;
   static const int kItemListStartOffset = 20;