Introduce an extension parameter which is used to customize the extension. It's available for exter…

extensions/browser/pending_extension_info.h

Index: extensions/browser/pending_extension_info.h
diff --git a/extensions/browser/pending_extension_info.h b/extensions/browser/pending_extension_info.h
index fd1d3aec4fdb0e0fcf9abcbae24fd4c59ff5b412..84ed67fb15d1b9fdff096ec34eea56cc7e5a3aa2 100644
--- a/extensions/browser/pending_extension_info.h
+++ b/extensions/browser/pending_extension_info.h
@@ -27,26 +27,29 @@ class PendingExtensionInfo {
  public:
   typedef bool (*ShouldAllowInstallPredicate)(const Extension*);
 
-  PendingExtensionInfo(
-      const std::string& id,
-      const GURL& update_url,
-      const Version& version,
-      ShouldAllowInstallPredicate should_allow_install,
-      bool is_from_sync,
-      bool install_silently,
-      Manifest::Location install_source,
-      int creation_flags,
-      bool mark_acknowledged);
+  PendingExtensionInfo(const std::string& id,
+                       const std::string& install_parameter,
+                       const GURL& update_url,
+                       const Version& version,
+                       ShouldAllowInstallPredicate should_allow_install,
+                       bool is_from_sync,
+                       bool install_silently,
+                       Manifest::Location install_source,
+                       int creation_flags,
+                       bool mark_acknowledged);
 
   // Required for STL container membership.  Should not be used directly.
   PendingExtensionInfo();
 
+  ~PendingExtensionInfo();
+
   // Consider two PendingExtensionInfos equal if their ids are equal.
   bool operator==(const PendingExtensionInfo& rhs) const;
 
   const std::string& id() const { return id_; }
   const GURL& update_url() const { return update_url_; }
   const Version& version() const { return version_; }
+  const std::string& install_parameter() const { return install_parameter_; }
 
   // ShouldAllowInstall() returns the result of running constructor argument
   // |should_allow_install| on an extension. After an extension is unpacked,
@@ -75,6 +78,7 @@ class PendingExtensionInfo {
 
   GURL update_url_;
   Version version_;
+  std::string install_parameter_;
 
   // When the extension is about to be installed, this function is
   // called.  If this function returns true, the install proceeds.  If