[Code Coverage] Clarify the differences between DCHECKs and standard asserts.

Bug: 849369
Change-Id: Iea7f9882faa1daaa4afa82f39c42776cfc4896ce
Reviewed-on: https://chromium-review.googlesource.com/1199704
Commit-Queue: Max Moroz <[email protected]>
Reviewed-by: Abhishek Arya <[email protected]>
Cr-Commit-Position: refs/heads/master@{#588052}
diff --git a/tools/code_coverage/coverage.py b/tools/code_coverage/coverage.py
index 688605d..0ad4f5e7 100755
--- a/tools/code_coverage/coverage.py
+++ b/tools/code_coverage/coverage.py
@@ -13,7 +13,9 @@
 
   * Example usage:
 
-  gn gen out/coverage --args='use_clang_coverage=true is_component_build=false'
+  gn gen out/coverage \\
+      --args='use_clang_coverage=true is_component_build=false \\
+              dcheck_always_on=true'
   gclient runhooks
   python tools/code_coverage/coverage.py crypto_unittests url_unittests \\
       -b out/coverage -o out/report -c 'out/coverage/crypto_unittests' \\