Make vertical-lr and vertical-rl versions of the tests that replace border-padding-pagination.html

border-padding-pagination.html exists for both these writing modes, and it won't be
used in the new implementation, so better make sure that we don't lose coverage.

R=jchaffraix@chromium.org

Review URL: https://codereview.chromium.org/510123002

git-svn-id: svn://svn.chromium.org/blink/trunk@181622 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add WebDocument::manifestURL().

BUG=410419

Review URL: https://codereview.chromium.org/535283003

git-svn-id: svn://svn.chromium.org/blink/trunk@181624 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Refactor PendingScript / HTMLScriptRunner.

Goal: PendingScript should know how to watch for its resource to load, and upper
layers (such as HTMLScriptRunner) should delegate the "how to watch for load"
logic to PendingScript, instead of accessing its resource directly.

In addition, a function to extract source code from PendingScript should be in
PendingScript, not in HTMLScriptRunner.

The refactoring is split off from https://codereview.chromium.org/368283002
(script streaming), but it makes sense as standalone too.

BUG=

Review URL: https://codereview.chromium.org/551293002

git-svn-id: svn://svn.chromium.org/blink/trunk@181627 bbb929c8-8fbe-4397-9dbb-9b2b20218538