[WIP] Use Optional<SkColor> instead of int64 for colors in Manifest.

content/browser/manifest/manifest_manager_host.cc

Index: content/browser/manifest/manifest_manager_host.cc
diff --git a/content/browser/manifest/manifest_manager_host.cc b/content/browser/manifest/manifest_manager_host.cc
index ea6557fa4e06f31faaf798462c6ea2973bc3644f..279908a83eb69995199eee73fb93999f33849ee4 100644
--- a/content/browser/manifest/manifest_manager_host.cc
+++ b/content/browser/manifest/manifest_manager_host.cc
@@ -141,15 +141,6 @@ void ManifestManagerHost::OnRequestManifestResponse(
                                    0, Manifest::kMaxIPCStringLength),
                                related_application.id.is_null());
   }
-  // theme_color and background_color are 32 bit unsigned integers with 64 bit
-  // integers simply being used to encode the occurence of an error. Therefore,
-  // any value outside the range of a 32 bit integer is invalid.
-  if (manifest.theme_color < std::numeric_limits<int32_t>::min() ||
-      manifest.theme_color > std::numeric_limits<int32_t>::max())
-    manifest.theme_color = Manifest::kInvalidOrMissingColor;
-  if (manifest.background_color < std::numeric_limits<int32_t>::min() ||
-      manifest.background_color > std::numeric_limits<int32_t>::max())
-    manifest.background_color = Manifest::kInvalidOrMissingColor;
 
   callback->Run(manifest_url, manifest);
   callbacks->Remove(request_id);