Add new user script injection point "document_idle" and make it the default.

Semantically, document-idle means "when the DOM is ready and layout has been idle for awhile", or more loosely, "as soon as we get around to it".

Right now this uses a simple heuristic. It injects scripts 200ms after DOMContentLoaded, or immediately after onload, whichever happens first.

BUG=26126
TEST=Manual. Extensions with content scripts should work.

Review URL: http://codereview.chromium.org/339064

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@30784 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 3 deletions

diff --git a/chrome/common/extensions/user_script.h b/chrome/common/extensions/user_script.h
index 28b3aae..bdd1e54 100644
--- a/chrome/common/extensions/user_script.h
+++ b/chrome/common/extensions/user_script.h
@@ -28,6 +28,10 @@ class UserScript {
                      // anything else happens.
     DOCUMENT_END,  // After the entire document is parsed. Same as
                    // DOMContentLoaded.
+    DOCUMENT_IDLE,  // Sometime after DOMContentLoaded, as soon as the document
+                    // is "idle". Currently this uses the simple heuristic of:
+                    // min(DOM_CONTENT_LOADED + TIMEOUT, ONLOAD), but no
+                    // particular injection point is guaranteed.
 
     RUN_LOCATION_LAST  // Leave this as the last item.
   };
@@ -88,9 +92,10 @@ class UserScript {
 
   typedef std::vector<File> FileList;
 
-  // Constructor. Default the run location to document end, which is like
-  // Greasemonkey and probably more useful for typical scripts.
-  UserScript() : run_location_(DOCUMENT_END) {}
+  // Constructor. Default the run location to document idle, which is similar
+  // to Greasemonkey but should result in better page load times for fast-
+  // loading pages.
+  UserScript() : run_location_(DOCUMENT_IDLE) {}
 
   // The place in the document to run the script.
   RunLocation run_location() const { return run_location_; }