Enable Media query evaluation in the preload scanner

This CL enables Media Query evaluation inside the preload scanner, without joining the main thread.
That is to enable resource fetching based on the media attribute, without hampering future resource fetching improvements.

Major changes:
* Added a MediaValues class that "freezes" the various media values needed for MQE when it is initialized.
* Initialize MediaValues and provide them to the PreloadScanner during its initialization.
* Run MQE inside the PreloadScanner, according to provided MediaValues.
* Removed mediaAttribute passing to the HTMLResourcePreloader, that runs on the main thread.

BUG=

Review URL: https://codereview.chromium.org/201813002

git-svn-id: svn://svn.chromium.org/blink/trunk@170314 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Cleanup run-bindings-tests and use filecmp (23% faster r-b-t)

The use of filecmp:
* speeds up r-b-t by 23% (if no diffs): (885 ms vs. 1.150 sec)
* uses only 1 process (if no diffs): 30 => 1
* if diffs, same speed
(can't measure difference, because filecmp is basically instantaneous on my machine)

Also some cleanup:
* remove dead code
* simplify temp file handling (caused build bot failures previously)
* don't catch exceptions, so easier to debug errors in CG
(because it's just one process now)

Currently r-b-t launches a separate diff(1) process for each file it compares.
Python has a built-in diff facility, which is extremely fast and avoids other processes.
This should make a big difference on Windows, meaning faster uploads for
Windows developers and less load on build bots.

Also a lot of the code is no longer necessary, after Terry's simplifications.
We can eliminate all the redundant temp file handling, and just need a simple
temp dir class.

R=haraken
BUG=341748

Review URL: https://codereview.chromium.org/216753002

git-svn-id: svn://svn.chromium.org/blink/trunk@170315 bbb929c8-8fbe-4397-9dbb-9b2b20218538