Lazily load extension API schemas

chrome/common/extensions/features/feature.h

Index: chrome/common/extensions/features/feature.h
diff --git a/chrome/common/extensions/features/feature.h b/chrome/common/extensions/features/feature.h
index 6eaa3a3b4f2106e6e74934a01a6c203b66946d06..791f761b0a5ea0fc8d01f4a6761faaf3be63096d 100644
--- a/chrome/common/extensions/features/feature.h
+++ b/chrome/common/extensions/features/feature.h
@@ -13,6 +13,8 @@
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/manifest.h"
 
+class GURL;
+
 namespace extensions {
 
 // Represents a single feature accessible to an extension developer, such as a
@@ -55,6 +57,7 @@ class Feature {
   enum AvailabilityResult {
     IS_AVAILABLE,
     NOT_FOUND_IN_WHITELIST,
+    INVALID_URL,
     INVALID_TYPE,
     INVALID_CONTEXT,
     INVALID_LOCATION,
@@ -149,11 +152,13 @@ class Feature {
   // Returns true if the feature is available to be used in the specified
   // extension and context.
   Availability IsAvailableToContext(const Extension* extension,
-                                    Context context) const {
-    return IsAvailableToContext(extension, context, GetCurrentPlatform());
+                                    Context context,
+                                    const GURL& url) const {
+    return IsAvailableToContext(extension, context, url, GetCurrentPlatform());
   }
   virtual Availability IsAvailableToContext(const Extension* extension,
                                             Context context,
+                                            const GURL& url,
                                             Platform platform) const = 0;
 
   virtual std::string GetAvailabilityMessage(