Cleanup: Move kChromeUIScheme constant into content namespace.

chrome/browser/content_settings/host_content_settings_map.cc

Index: chrome/browser/content_settings/host_content_settings_map.cc
diff --git a/chrome/browser/content_settings/host_content_settings_map.cc b/chrome/browser/content_settings/host_content_settings_map.cc
index 7b5cd0e56918a87f8d4a374b3359697f6bec8038..5871189c1ff49085e1a19ad12e75a6272cc64eb2 100644
--- a/chrome/browser/content_settings/host_content_settings_map.cc
+++ b/chrome/browser/content_settings/host_content_settings_map.cc
@@ -546,7 +546,7 @@ bool HostContentSettingsMap::ShouldAllowAllContent(
       content_type == CONTENT_SETTINGS_TYPE_MIDI_SYSEX) {
     return false;
   }
-  if (secondary_url.SchemeIs(chrome::kChromeUIScheme) &&
+  if (secondary_url.SchemeIs(content::kChromeUIScheme) &&
       content_type == CONTENT_SETTINGS_TYPE_COOKIES &&
       primary_url.SchemeIsSecure()) {
     return true;
@@ -565,7 +565,7 @@ bool HostContentSettingsMap::ShouldAllowAllContent(
     }
   }
   return primary_url.SchemeIs(chrome::kChromeDevToolsScheme) ||
-         primary_url.SchemeIs(chrome::kChromeUIScheme);
+         primary_url.SchemeIs(content::kChromeUIScheme);
 }
 
 base::Value* HostContentSettingsMap::GetWebsiteSetting(