Add some .h files under chrome/browser to .gn files.

BUG=661774

Review-Url: https://codereview.chromium.org/2838813005
Cr-Commit-Position: refs/heads/master@{#467405}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 84b5bee..f929816 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -2984,6 +2984,7 @@
       "android/tab_state.h",
       "android/tab_web_contents_delegate_android.cc",
       "android/tab_web_contents_delegate_android.h",
+      "android/thumbnail/scoped_ptr_expiring_cache.h",
       "android/thumbnail/thumbnail.cc",
       "android/thumbnail/thumbnail.h",
       "android/thumbnail/thumbnail_cache.cc",