Rename the build/ directory.

GYP related files went in gypfiles/, and the gni went in gni/ this
changes frees up the build/ directory name for Chromium's build/
directory.

BUG=angleproject:1569

Change-Id: I76fe343d569239c2732ba87986fcf7debc21d417
Reviewed-on: https://chromium-review.googlesource.com/403029
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/doc/DebuggingTips.md b/doc/DebuggingTips.md
index 07c7e10..f7bcf24 100644
--- a/doc/DebuggingTips.md
+++ b/doc/DebuggingTips.md
@@ -17,7 +17,7 @@
 For example, to trace a run of `hello_triangle`, assuming you are using the ninja gyp generator and the apitrace executables are in `$PATH`:
 
 ```
-./build/gyp_angle -D angle_link_glx=1 -D angle_gl_library_type=static_library
+./gyp/gyp_angle -D angle_link_glx=1 -D angle_gl_library_type=static_library
 ninja -C out/Debug
 export TRACE_LIBGL="/usr/lib/libGL.so.1" # may require a different path
 apitrace trace -o mytrace ./out/Debug/hello_triangle