Move some extension manifest consistency checks to BackgroundManifestHandler.

chrome/common/extensions/background_info.h

Index: chrome/common/extensions/background_info.h
diff --git a/chrome/common/extensions/background_info.h b/chrome/common/extensions/background_info.h
index 881b94717599f7dae4bab0d753b50b73cffdebf1..5807a3007f690dd4c8f6a7f8a87b541c5b2c0785 100644
--- a/chrome/common/extensions/background_info.h
+++ b/chrome/common/extensions/background_info.h
@@ -32,6 +32,14 @@ class BackgroundInfo : public Extension::ManifestData {
     return background_url_.is_valid() || !background_scripts_.empty();
   }
 
+  bool has_persistent_background_page() const {
+    return has_background_page() && is_persistent_;
+  }
+
+  bool has_lazy_background_page() const {
+    return has_background_page() && !is_persistent_;
+  }
+
   bool Parse(const Extension* extension, string16* error);
 
  private:
@@ -75,6 +83,7 @@ class BackgroundManifestHandler : public ManifestHandler {
   virtual bool Validate(const Extension* extension,
                         std::string* error,
                         std::vector<InstallWarning>* warnings) const OVERRIDE;
+  virtual bool AlwaysParseForType(Manifest::Type type) const OVERRIDE;
 
  private:
   virtual const std::vector<std::string> Keys() const OVERRIDE;