Compile blink/common/ with -Wshadow.

No code changes required.

Bug: 294205
Change-Id: I39a0bc14e444a9bbff70f57a9866acda8a9c0c87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2472040Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817539}

third_party/blink/common/BUILD.gn

@@ -62,7 +62,10 @@ source_set("common") {
     "//third_party/blink/public/common",
   ]
 
-  configs += [ ":blink_common_implementation" ]
+  configs += [
+    ":blink_common_implementation",
+    "//build/config/compiler:noshadowing",
+  ]
 
   sources = [
     # NOTE: Please do not add public headers that need to be referenced from