Add whitelist support for grit repack steps.

tools/resources/find_used_resources.py

Index: tools/resources/find_used_resources.py
diff --git a/tools/resources/find_used_resources.py b/tools/resources/find_used_resources.py
index 60af3e5197f1a10d3dfd1ff6d96c156876a18f35..6a3ecdf2bc4a347f797fa98594aba8ac09bd28f8 100755
--- a/tools/resources/find_used_resources.py
+++ b/tools/resources/find_used_resources.py
@@ -18,7 +18,7 @@ script parses out the list of used resource ids. These resource ids show up in
 the build output after building Chrome with gyp variable
 enable_resource_whitelist_generation set to 1. This gyp flag causes the compiler
 to print out a UnknownPragma message every time a resource id is used. E.g.:
-foo.cc:22:0: warning: ignoring #pragma IDS_FOO_BAR  [-Wunknown-pragmas]
+foo.cc:22:0: warning: ignoring #pragma 12345  [-Wunknown-pragmas]

[newt (away), 2014/03/31 17:45:14]

I think it would be helpful to change this message to something like:

  warning: ignoring #pragma whitelisted-resource-12345 [-Wunknown-pragmas]

that'll help someone who sees the build output a) be slightly less confused, and
b) grep for the code that causes the warning and discover that it's 100%
intentional.

[aurimas (slooooooooow), 2014/03/31 17:54:21]

Done.

 
 """
 
@@ -29,7 +29,7 @@ def GetResourceIdsInPragmaWarnings(input):
   """
   used_resources = set()
   unknown_pragma_warning_pattern = re.compile('warning: ignoring #pragma '
-      '(?P<resource_id>[A-Z0-9_]*)  \[-Wunknown-pragmas\]')
+      '(?P<resource_id>[0-9]*)  \[-Wunknown-pragmas\]')
   for ln in input:
     match = unknown_pragma_warning_pattern.search(ln)
     if match: