clang: Enable -Wfor-loop-analysis.

build/common.gypi

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 2615 matching lines @@
           'mac_release_optimization%': '2', # Use -O2 unless overridden
           'mac_debug_optimization%': '0',   # Use -O0 unless overridden
         }],
         ['OS=="android"', {
           'host_os%': '<(host_os)',  # See comment above chromium_code.
         }],
       ],
       'clang_warning_flags': [
         '-Wheader-hygiene',
 
+        # 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).
+
         # Don't die on dtoa code that uses a char as an array index.
         # This is required solely for base/third_party/dmg_fp/dtoa.cc.
         '-Wno-char-subscripts',
 
         # TODO(thakis): This used to be implied by -Wno-unused-function,
         # which we no longer use. Check if it makes sense to remove
         # this as well. http://crbug.com/316352
         '-Wno-unneeded-internal-declaration',
 
         # Warns on switches on enums that cover all enum values but
@@ skipping 3736 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }