Add android_webview/public/ to manual-paths-to-ignore

It doesn't depend on //base, which is needed for CheckedPtr

Bug: 1069567
Change-Id: I4eb2d7e46b2a018f7de08d69aef32e0e3d23aa59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2440075
Commit-Queue: Bartek Nowierski <bartekn@chromium.org>
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Auto-Submit: Bartek Nowierski <bartekn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814041}

tools/clang/rewrite_raw_ptr_fields/manual-paths-to-ignore.txt

@@ -19,11 +19,15 @@ base/allocator/
 # Exclude - deprecated and contains legacy C++ and pre-C++11 code.
 ppapi/
 
-# Exclude tools that do not ship in the Chrome binary.
+# Exclude tools that do not ship in the Chrome binary. Can't depend on //base.
 base/android/linker/
 tools/
 net/tools/
 
+# The folder holds headers that are duplicated in the Android source and need to
+# provide a stable C ABI. Can't depend on //base.
+android_webview/public/
+
 # Exclude code that only runs inside a renderer process - renderer
 # processes are excluded for now from the MiraclePtr project scope,
 # because they are sensitive to performance regressions (to a much higher