Move simple png encoding for image_diff into tools/

android_webview/tools/third_party_files_whitelist.txt

Index: android_webview/tools/third_party_files_whitelist.txt
diff --git a/android_webview/tools/third_party_files_whitelist.txt b/android_webview/tools/third_party_files_whitelist.txt
index 190bcb64c03b752b19a12b0d90989fa5e83a80c7..843851526c54152c9ca55c9b94504e7ed51d4018 100644
--- a/android_webview/tools/third_party_files_whitelist.txt
+++ b/android_webview/tools/third_party_files_whitelist.txt
@@ -147,6 +147,9 @@ net/socket/ssl_client_socket_nss.cc
 skia/config/SkUserConfig.h
 # Contains word 'copyright' in comments.
 tools/gen_keyboard_overlay_data/gen_keyboard_overlay_data.py
+# This third-party code is taken from Mozilla, but is copyright Google and has
+# been re-licensed under the Chromium license.
+tools/imagediff/image_diff_png.cc
 # Copyright Ero Carrera; BSD license. Tool only.
 tools/symsrc/pefile.py
 # Copyright The Chromium Authors, Sun Microsystems Inc, the V8 project authors;
@@ -193,9 +196,6 @@ webkit/child/multipart_response_delegate.h
 # Copyright Tim Copperfield and Christian Dywan; LGPL license. Not used on
 # Android.
 webkit/common/cursors/webcursor_gtk_data.h
-# This third-party code is taken from Mozilla, but is copyright Google and has
-# been re-licensed under the Chromium license.
-webkit/support/webkit_support_gfx.cc
 # Copyright Apple, Inc, Graham Dennis and Eric Seidel; BSD license. Tool only
 webkit/support/mac/DumpRenderTreePasteboard.h
 # Copyright Apple, Inc, Graham Dennis and Eric Seidel; BSD license. Tool only