Support redirects by regular expression in declarative WebRequest API

chrome/common/extensions/api/declarative_web_request.json

Index: chrome/common/extensions/api/declarative_web_request.json
diff --git a/chrome/common/extensions/api/declarative_web_request.json b/chrome/common/extensions/api/declarative_web_request.json
index 0ab322226d3023a9d283712f2371c996e589c70a..19b010ef258e3477b8a8f311c0896615f58db517 100644
--- a/chrome/common/extensions/api/declarative_web_request.json
+++ b/chrome/common/extensions/api/declarative_web_request.json
@@ -66,6 +66,25 @@
         }
       },
       {
+        "id": "declarativeWebRequest.RedirectByRegEx",
+        "description": "Redirects a request by applying a regular expression on the URL. The regular expressions support temporarily the <a href=\"http://www.unicode.org/reports/tr18/\">ICU syntax</a> with $1 to reference capture group 1. This will be replaced with the <a href=\"http://code.google.com/p/re2/wiki/Syntax\">RE2 syntax</a> which uses \\1 to reference capture group 1 before the API is released into the beta release of Google Chrome.",

[Matt Perry, 2012/05/30 19:18:26]

Can we just do a string.replaceAll('\\', '$') for the time being, to avoid
having to mention this caveat? (or maybe it has to be replaceAll("\N", "$N") for
N=1..9)

[battre, 2012/05/31 16:01:32]

I looked up the individual capture group definitions and have done it properly.
You may notice that I have written some code that is currently not used (but
unit tested). I figured it would be easier to write the code now and just delete
some code once we migrate to RE2.

I am planning to leave both options as input syntax because the $ notation is
pretty common in the extension world because JavaScript RegExes use $. Note,
though, that JavaScript's RegExes are more powerful. I am not sure whether we
should mention "Perl" because it is significantly more powerful.

+        "type": "object",
+        "properties": {
+          "instanceType": {
+            "type": "string", "enum": ["declarativeWebRequest.RedirectByRegEx"],
+            "nodoc": true
+          },
+          "from": {
+            "type": "string",
+            "description": "A match pattern that may contain capture groups."
+          },
+          "to": {
+            "type": "string",
+            "description": "Destination pattern."
+          }
+        }
+      },
+      {
         "id": "declarativeWebRequest.SetRequestHeader",
         "description": "Sets the request header of the specified name to the specified value. If a header with the specified name did not exist before, a new one is created. Header name comparison is always case-insensitive. Each request header name occurs only once in each request.",
         "type": "object",
@@ -169,6 +188,7 @@
             "declarativeWebRequest.RedirectRequest",
             "declarativeWebRequest.RedirectToTransparentImage",
             "declarativeWebRequest.RedirectToEmptyDocument",
+            "declarativeWebRequest.RedirectByRegEx",
             "declarativeWebRequest.SetRequestHeader",
             "declarativeWebRequest.RemoveRequestHeader",
             "declarativeWebRequest.RemoveResponseHeader",