clang: Enable -Wfor-loop-analysis.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index b7d82a4687b72622526eb37c3334042756e9c5ef..e732de7779be8f77f2dd8c36c4434f1fce4c90a3 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -830,6 +830,12 @@ config("default_warnings") {
 
   if (is_clang) {
     cflags += [
+      # TODO(thakis): Add -Wfor-loop-analysis to -Wall in clang, remove this:
+      "-Wfor-loop-analysis",
+
+      # TODO(thakis): Consider -Wloop-analysis (turns on
+      # -Wrange-loop-analysis too).
+
       # This warns on using ints as initializers for floats in
       # initializer lists (e.g. |int a = f(); CGSize s = { a, a };|),
       # which happens in several places in chrome code. Not sure if