Build third-party code with -Wall, build chromium_code with -Wextra on Linux

third_party/android_protobuf/BUILD.gn

Index: third_party/android_protobuf/BUILD.gn
diff --git a/third_party/android_protobuf/BUILD.gn b/third_party/android_protobuf/BUILD.gn
index 266ca83a7ae5631ac756fc16abcefc42b28a0756..387d028bd20279cfa2809d03e39d433a1fd7ea96 100644
--- a/third_party/android_protobuf/BUILD.gn
+++ b/third_party/android_protobuf/BUILD.gn
@@ -3,10 +3,26 @@
 # found in the LICENSE file.
 
 if (current_toolchain == host_toolchain) {
+  config("android_protoc_warnings") {
+    if (is_clang) {

[Lei Zhang, 2015/12/31 00:07:37]

No if statement since the gyp version has these in a cflags block and not a
clang_warning_flags block?

[Nico, 2015/12/31 02:44:17]

Done, good point, thanks.

+      cflags = [
+        "-Wno-null-conversion",
+        "-Wno-tautological-undefined-compare",
+        "-Wno-unused-function",
+        "-Wno-unused-local-typedef",
+      ]
+    }
+  }
+
   # GYP: //third_party/android_protobuf/android_protobuf.gyp:android_protoc
   executable("android_protoc") {
     configs -= [ "//build/config/compiler:chromium_code" ]
-    configs += [ "//build/config/compiler:no_chromium_code" ]
+    configs += [
+      "//build/config/compiler:no_chromium_code",
+
+      # Must be after no_chromium_code so warning flags are ordered correctly.
+      ":android_protoc_warnings",
+    ]
 
     deps = [
       "//build/config/sanitizers:deps",
@@ -114,12 +130,6 @@ if (current_toolchain == host_toolchain) {
       "src/src",
     ]
 
-    if (is_clang) {
-      cflags = [
-        "-Wno-null-conversion",
-        "-Wno-tautological-undefined-compare",
-      ]
-    }
     defines = [
       # This macro must be defined to suppress the use
       # of dynamic_cast<>, which requires RTTI.