Refactor how font scale factor appears in the emulation panel

This patch refactors the confusing font scale factor setting. A
screenshot is available at http://pr.gg/asnew.png

Changes included in this patch:
1) Added updated tooltips for DPR, text autosizing, and the use android
   text metrics checkbox. This patch also moves the tooltips
   to be on both the input element and the associated label.
2) Removes the font scale factor textbox. Instead of manually entering
   this value, it will automatically be calculated if the new
   "Use Android font metrics" checkbox is checked.
3) Adds a new "Use Android font metrics" checkbox and auto-check it
   based on which emulation preset is chosen. When text autosizing
   is disabled, this checkbox will be disabled.
4) Minor refactoring of metrics.fontScaleFactor() which now computes
   the factor on-demand (it's cheap).

Some usecases:
If an iOS device is emulated, the text autosizing box will be checked
but the android font metrics box will not.

If an Android device is emulated, both checkboxes are checked.

If a custom device is being emulated, the user can choose whether to
use android's font metrics.

BUG=319092

Review URL: https://codereview.chromium.org/73203003

git-svn-id: svn://svn.chromium.org/blink/trunk@162250 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r162223

http://src.chromium.org/viewvc/blink?view=revision&revision=162223

TBR=mkwst@chromium.org

Review URL: https://codereview.chromium.org/59753009

git-svn-id: svn://svn.chromium.org/blink/trunk@162251 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Split CSSTokenizer out of CSSParser

This is a first take at moving CSSTokenizer out of CSSParser,
some related functions were not moved along as the patch was
taking epic proportions already.

BUG=320488

Review URL: https://codereview.chromium.org/74943002

git-svn-id: svn://svn.chromium.org/blink/trunk@162252 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Factor out delivery of throttled progress event.

To prepare for follow-on changes to progress event handling, split out
the delivery of single XHR progress events into a separate method.

R=
BUG=315488

Review URL: https://codereview.chromium.org/75103006

git-svn-id: svn://svn.chromium.org/blink/trunk@162253 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move delivery of upload 'progress' events to XMLHttpRequestUpload.

Have the XMLHttpRequestUpload object handle dispatching of its
'progress' events, and at the same time keep track of the last
progress data reported.

While the latter state isn't directly made use of here, follow-on
changes to handle 'progress' events during XHR request errors will
depend on having it available.

R=
BUG=315488

Review URL: https://codereview.chromium.org/63033008

git-svn-id: svn://svn.chromium.org/blink/trunk@162254 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename TextAutosizingFontScaleFactor to AccessibilityFontScaleFactor

There are currently two font scale factors in Settings:
1) deviceScaleAdjustment - represents the additional fudge factor
  applied to fonts in Android. In the future this may handle other
  scale adjustments.
2) textAutosizingFontScaleFactor - this is plumbed in as the
  accessibility slider value (under settings->accessibility in Chrome).

This patch contains two refactorings:
1) Rename TextAutosizingFontScaleFactor to AccessibilityFontScaleFactor.
2) Update the inspector emulation to override the deviceScaleAdjustment
  instead of the accessibility scale factor. In an unfortunate naming
  accident, the inspector uses "device scale factor" to mean DPR so I
  have left the override as "overrideFontScaleFactor". Note that this does
  have a change in behavior as the device scale adjustment is only
  applied in some situations whereas the accessibility scale factor is
  always applied.

This patch requires a two-sided change due to the API name change.

BUG=320193

Review URL: https://codereview.chromium.org/74663002

git-svn-id: svn://svn.chromium.org/blink/trunk@162255 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: [ActiveDOMObject] interface

First interface extended attribute.

Each of these requires a separate test IDL file,
as do combinations of extended attributes that interact,
due to having one interface per file.

The test interface can be *empty* if the extended attribute 
only affects the overall interface code (e.g., [ActiveDOMObject]),
but needs to have attributes or methods if these are also affected
(e.g., [CheckSecurity]).

I will be primarily activating existing tests by removing the "SKIP" from
run-bindings-tests, and writing new tests if necessary.
Following existing naming, these are generally called
Test<ExtAttr>Interface.idl
...for some value of <ExtAttr>.

This CL also renames an incorrectly named file:
TestActiveDOMObject.idl => TestCheckSecurityInterface.idl
...and adds a new test file:
TestActiveDOMObjectInterface.idl

BUG=239771
NOTRY=true

Review URL: https://codereview.chromium.org/74783008

git-svn-id: svn://svn.chromium.org/blink/trunk@162256 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Change WebVTT to VTT in non-public API symbols.
This is a follow-up on https://codereview.chromium.org/68203028, which renamed files to use VTT.

BUG=320417

Review URL: https://codereview.chromium.org/65593003

git-svn-id: svn://svn.chromium.org/blink/trunk@162259 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: Sync Python to r162223

Sync per:
Improve remaining TypeErrors in bindings code.
https://codereview.chromium.org/36843003/

BUG=239771
NOTRY=true
TBR=haraken

Review URL: https://codereview.chromium.org/71203007

git-svn-id: svn://svn.chromium.org/blink/trunk@162260 bbb929c8-8fbe-4397-9dbb-9b2b20218538