net: Always import //tools/grit/grit_rule.gni.

The bug that didn't allow us to import a file multiple times
(crbug.com/393704) has been fixed
(https://chromium.googlesource.com/chromium/src/+/c2f83406a117e0bdd8eb57bf64bb168f2b01eb1b).

Tested on Linux with the following command lines:

$ gn gen out-gn/Release --args='is_debug=false is_component_build=false symbol_level=1'

$ gn gen out-gn-android/Release '--args=target_os="android" is_debug=false is_component_build=false symbol_level=1 dcheck_always_on=true' --check

BUG=None
TEST=see above
[email protected]

Review URL: https://codereview.chromium.org/1380103008

Cr-Commit-Position: refs/heads/master@{#352706}
1 file changed