Fix most GN clang errors.

breakpad/BUILD.gn

Index: breakpad/BUILD.gn
diff --git a/breakpad/BUILD.gn b/breakpad/BUILD.gn
index 2c0ae49abbde09b0922b004f451e26cac916793f..53454ac5a478dbc7a43ee9748758d0e9c32a8cff 100644
--- a/breakpad/BUILD.gn
+++ b/breakpad/BUILD.gn
@@ -420,6 +420,8 @@ if (is_linux && current_toolchain == host_toolchain) {
       "src/common/string_conversion.h",
     ]
 
+    configs -= [ "//build/config/compiler:chromium_code" ]

[DaleCurtis, 2014/07/17 18:29:49]

These names aren't very helpful, something like strict_warnings,
relaxed_warnings might be easier to follow.

[brettw, 2014/07/17 19:42:42]

I just emulated gyp's "chromium_code: 1" since it's what people are used to. You
might be right, but it's very difficult to change at this point.

+    configs += [ "//build/config/compiler:no_chromium_code" ]
     direct_dependent_configs = [ ":breakpad_client_config" ]
 
     # Android NDK toolchain doesn't support -mimplicit-it=always
@@ -551,7 +553,8 @@ if (is_linux && current_toolchain == host_toolchain) {
     ]
 
     # This file has an unused variable warning.
-    cflags = [ "-Wno-unused-variable" ]
+    configs -= [ "//build/config/compiler:chromium_code" ]
+    configs += [ "//build/config/compiler:no_chromium_code" ]
 
     deps = [ ":breakpad_client" ]