Enable -Wextra-semi in non-cros non-chromecast non-fuzzer linux builds that have DCHECKs enabled.

Only enables the warning for chromium_code.n

Also fix the last few -Wextra-semi instances in sanitizer and linux/ozone builds.

Getting to this state required fixing > 3000 unique warnings in 15+ different
repositories.  If this breaks some internal-only build somewhere, either consider
using no_chromium_code for your internal code, or fix the warnings -- it's
pretty easy. (Build with treat_warnings_as_errors=false, then open the error log
in vim, run `:%g/warning:/t$` to copy the warnings to the end of the buffer,
remove all but just those lines, run `:sort u` to get uniques, then save as
`tmp.txt` and run `:cf %` and then use something like `:map m :w<cr>:cn<cr>`
to go through them quickly.)

TBR=rsesek

Bug: 926235
Change-Id: Ica629737523ff6bbd756edc44d182f35ff6cf8ac
Reviewed-on: https://chromium-review.googlesource.com/c/1483396Reviewed-by: Scott Violet <sky@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634826}

build/config/compiler/BUILD.gn

@@ -9,6 +9,7 @@ import("//build/config/chromecast_build.gni")
 import("//build/config/clang/clang.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/coverage/coverage.gni")
+import("//build/config/dcheck_always_on.gni")
 import("//build/config/host_byteorder.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
@@ -1586,6 +1587,13 @@ config("chromium_code") {
       # https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
       "-Wthread-safety",
     ]
+
+    # TODO(thakis): Enable this for more platforms, https://crbug.com/926235
+    has_dchecks = is_debug || dcheck_always_on
+    if (has_dchecks && is_linux && target_os != "chromeos" && !is_chromecast &&
+        !use_libfuzzer && !is_debug) {
+      cflags += [ "-Wextra-semi" ]
+    }
   }
 
   configs = [ ":default_warnings" ]

services/service_manager/sandbox/linux/sandbox_linux.h

@@ -198,7 +198,7 @@ class SERVICE_MANAGER_SANDBOX_EXPORT SandboxLinux {
 #if BUILDFLAG(USING_SANITIZER)
   __sanitizer_sandbox_arguments* sanitizer_args() const {
     return sanitizer_args_.get();
-  };
+  }
 #endif
 
   // A BrokerProcess is a helper that is started before the sandbox is engaged,

ui/ozone/platform/wayland/xdg_popup_wrapper_v6.h

@@ -41,7 +41,6 @@ class XDGPopupWrapperV6 : public XDGPopupWrapper {
 
  private:
   WaylandWindow* wayland_window_ = nullptr;
-  ;
   std::unique_ptr<XDGSurfaceWrapper> zxdg_surface_v6_;
   wl::Object<zxdg_popup_v6> xdg_popup_;