Enforce comment formatting in wtf/, web/

BUG=563793

Review-Url: https://codereview.chromium.org/2390853002
Cr-Commit-Position: refs/heads/master@{#422573}

third_party/WebKit/Source/web/.clang-format

+# TODO(thakis): Remove this once Source/.clang-format no longer says
+# `ReflowComments: false`.
+BasedOnStyle: Chromium
+Standard: Cpp11
+ReflowComments: true

third_party/WebKit/Source/wtf/.clang-format

+# TODO(thakis): Remove this once Source/.clang-format no longer says
+# `ReflowComments: false`.
+BasedOnStyle: Chromium
+Standard: Cpp11
+ReflowComments: true