Remove explicit -Wextra-semi, -Winconsistent-missing-override flags.

They're  enabled via the chromium_code config already these days.
No intended behavior change.

Bug: chromium:926235,chromium:428099

Change-Id: I6927d6e3ec85f40454da61969d7a22dfabef1bde
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1564781
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index 534982f..160b516 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -125,19 +125,10 @@
     ]
   }
   if (is_clang) {
-    if (!is_fuchsia) {
-      cflags += [
-        # Remove when crbug.com/926235 is resolved.
-        "-Wextra-semi",
-      ]
-    }
-
     cflags += [
       # Enable after anglebug.com/3128 is fixed.
       # "-Wextra-semi-stmt",
 
-      # Remove when crbug.com/428099 is resolved.
-      "-Winconsistent-missing-override",
       "-Wnon-virtual-dtor",
       "-Wunneeded-internal-declaration",
     ]