VCD: Add ForceEnableFaceAe flag

We can use this flag to test face ae support camera.

Bug: b/173084289
Test: Check /run/camera/force_enable_ae created/deleted correctly
Change-Id: I22f59bd7b7d577ad5d6434292a1f5a7f7485303c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2874505
Commit-Queue: Hsu Wei-Cheng <[email protected]>
Reviewed-by: Ricky Liang <[email protected]>
Cr-Commit-Position: refs/heads/master@{#879680}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 7d6614b..4b76258 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -2299,6 +2299,9 @@
 extern const char kPreferConstantFrameRateName[];
 extern const char kPreferConstantFrameRateDescription[];
 
+extern const char kForceEnableFaceAeName[];
+extern const char kForceEnableFaceAeDescription[];
+
 extern const char kCategoricalSearchName[];
 extern const char kCategoricalSearchDescription[];