Unofficial gardening. fast/js/regress/HashMap-put-get-iterate-keys.html got slower after the most recent V8 roll.

BUG=259934
TBR=eseidel

Review URL: https://codereview.chromium.org/19060003

git-svn-id: svn://svn.chromium.org/blink/trunk@154137 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move logic for creating a new window to a separate file.

This logic is currently spread between DOMWindow.cpp and FrameLoader.cpp, in
two different static functions. These function could certainly be cleaned up,
but isolating them seems to be a good start.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/19104002

git-svn-id: svn://svn.chromium.org/blink/trunk@154138 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make CachedResource initiator type names static strings.

These are passed from the worker thread to the main thread, so using
thread local storage is no good. Plus, there's no reason to have
duplicate strings for each thread.

BUG=237801

Review URL: https://chromiumcodereview.appspot.com/18490004

git-svn-id: svn://svn.chromium.org/blink/trunk@154139 bbb929c8-8fbe-4397-9dbb-9b2b20218538