Add early-injection capability to user scripts. I haven't yet

chrome/common/extensions/user_script.h

Index: chrome/common/extensions/user_script.h
diff --git a/chrome/common/extensions/user_script.h b/chrome/common/extensions/user_script.h
index 6453c8ec4680bcebc6a052600ce7149f4819f742..671f158285a57b55e7e803ce110e030f6ead0d98 100644
--- a/chrome/common/extensions/user_script.h
+++ b/chrome/common/extensions/user_script.h
@@ -17,7 +17,19 @@
 // extension.
 class UserScript {
  public:
-  UserScript(){}
+  // Locations that user scripts can be run inside the document.
+  enum RunLocation {
+    DOCUMENT_START,  // After the documentElemnet is created, but before
+                     // anything else happens.
+    DOCUMENT_END,  // After the entire document is parsed. Same as
+                   // DOMContentLoaded.
+
+    RUN_LOCATION_LAST  // Leave this as the last item.
+  };
+
+  // Constructor. Default the run location to document end, which is like
+  // Greasemonkey and probably more useful for typical scripts.
+  UserScript() : run_location_(DOCUMENT_END) {}
 
   // The URL to retrieve the content of this script at.
   const GURL& url() const { return url_; }
@@ -27,6 +39,10 @@ class UserScript {
   const FilePath& path() const { return path_; }
   void set_path(const FilePath& path) { path_ = path; }
 
+  // The place in the document to run the script.
+  RunLocation run_location() const { return run_location_; }
+  void set_run_location(RunLocation location) { run_location_ = location; }
+
   // The globs, if any, that determine which pages this script runs against.
   // These are only used with "standalone" Greasemonkey-like user scripts.
   const std::vector<std::string>& globs() const { return globs_; }
@@ -60,6 +76,9 @@ class UserScript {
   // The path to the content of the script.
   FilePath path_;
 
+  // The location to run the script inside the document.
+  RunLocation run_location_;
+
   // Greasemonkey-style globs that determine pages to inject the script into.
   // These are only used with standalone scripts.
   std::vector<std::string> globs_;