Add comment to ANGLE test main import.

Bug: angleproject:2995
Change-Id: I4f24ff112247c512c8721d45022f1d7253c892ec
Tbr: [email protected]
Reviewed-on: https://chromium-review.googlesource.com/c/1391950
Reviewed-by: Jamie Madill <[email protected]>
Commit-Queue: Jamie Madill <[email protected]>
Cr-Commit-Position: refs/heads/master@{#619162}
diff --git a/gpu/angle_end2end_tests_main.cc b/gpu/angle_end2end_tests_main.cc
index cf0206a..e6fde85 100644
--- a/gpu/angle_end2end_tests_main.cc
+++ b/gpu/angle_end2end_tests_main.cc
@@ -18,6 +18,8 @@
 
 }  // namespace
 
+// Located in third_party/angle/src/tests/test_utils/ANGLETest.cpp.
+// Defined here so we can avoid depending on the ANGLE headers.
 void ANGLEProcessTestArgs(int *argc, char *argv[]);
 
 int main(int argc, char** argv) {