GN: just new deps
These just are the DEPS changes from the previous GN CL, each rolled up to head.
I've removed the hooks to fetch GN and Clang... will have to figure out how to
deal with .gclient files in different places later.
BUG=skia:5452
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2087403002
Review-Url: https://codereview.chromium.org/2087403002
diff --git a/.gitignore b/.gitignore
index 9fb5a30..37da2da 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,7 @@
tools/skp/page_sets/data/*.json
tools/skp/page_sets/data/*.wpr
xcodebuild
+
+build
+buildtools
+tools/clang