Privacy Blacklist Unblock...

Privacy Blacklist Unblock

Summary
-------

Mostly implemented the unblocking for visual resources for the Privacy Blacklist.
Merging now before I leave. Eveything here only has effect if the --privacy-blacklist
flag specifies a Privacy Blacklist.

Detailed Changes
----------------

[chrome/browser/resources/privacy_blacklist.html]

- Replaced the about:blank place-holder with variable to set the unblock link.

- Open the Privacy Blacklist provider page in a new tab. This works around an
  issue where such request for a full-page (rather than a sub-resource) gets
  blocked indefinitely.

[chrome/browser/render_host/resource_dispatcher_host.h]

- Added a BlockedResponse member which is now a class rather than a namespace,
  see below for more information.

[chrome/browser/render_host/resource_dispatcher_host.cc]

- Generate headers for the blocked response to redirect to the chrome-blocked URL
  which prevents an enclosing page from reading the URL of the unblock link. This
  was suggested by Darin to avoid scripted bypassing of blocked contents.

- Recover the original URL for blocked content, in order to fetch it during
  unblocking.

- Do not create CrossSiteResourceHandler when an unblocked link is requested.
  Otherwise the request never resumes as the blocked page never gets closed
  since it is not a real page.

[chrome/browser/privacy_blacklist/blocked_response.cc]

- Defined chrome-block and chrome-unblock URL schemes. The block scheme is used
  to return the blocked response. The unblock scheme is used request a blocked
  resource's URL without being intercepted by the Privacy Blacklist.

- Defined a hash function for a blocked resource as its address in memory.
  Function to reverse the hash is therefore trivial.

- Added a function to return headers for a blocked response.

- Added a function to generate a block URL from a requested one.

- Added a function to get an unblock URL from a requested one.

- Added a function to return the original URL for a blocked one.

[chrome/browser/privacy_blacklist/blocked_response.h]

- Made the BlockedResponse namespace into a class.

- Created a member set to keep all the blocked resources URL.

BUG=16932
TEST=none
TBR=darin


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=27719