Rename buildflag_headers for consistency

This updates ppapi.

Targets go from foo_features to foo_buildflags
And similarly the header now has buildflags in the name.

BUG=814485
TEST=covered by build
[email protected]

Change-Id: I25f990ebd1e7f8530ddd0cee24dba31c88a45fae
Reviewed-on: https://chromium-review.googlesource.com/980921
Reviewed-by: Scott Violet <[email protected]>
Reviewed-by: Xiaohan Wang <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Commit-Queue: Scott Violet <[email protected]>
Cr-Commit-Position: refs/heads/master@{#546312}
diff --git a/chrome/DEPS b/chrome/DEPS
index 68fab23..b05b1838 100644
--- a/chrome/DEPS
+++ b/chrome/DEPS
@@ -27,7 +27,7 @@
   "+media/media_buildflags.h",
   "+mojo/common",
   "+mojo/public",
-  "+ppapi/features",
+  "+ppapi/buildflags",
 
   # Don't allow inclusion of these other libs we shouldn't be calling directly.
   "-webkit",