Reapply again "Update scrollbars on pageScaleFactor change"

Change in the first reapplication:
Fixed the issue when the pageScaleFactor is set before a frame has
its view.

Change in this reapplication:
Fixed the issue of scrollbar layer creation (crbug.com/233866)
by calling visibleContentsResized() when existence of overlay scrollbars changes.

> Original description:
>
> Calls updateScrollbars() when pageScaleFactor changed.
> Changed updateScrollbars() to avoid unnecessary relayout for overlay scrollbars.

> Original BUG=181315
> Original TEST=WebFrameTest.setPageScaleFactorWithOverlayScrollbarsDoesNotLayout, WebFrameTest.pageScaleFactorUpdatesScrollbars
>
> Original Review URL: https://chromiumcodereview.appspot.com/13671002
>
> BUG=231002
> TEST=WebFrameTest.setPageScaleFactorBeforeFrameHasView

> Review URL: https://codereview.chromium.org/14200023

> git-svn-id: svn://svn.chromium.org/blink/trunk@148574 bbb929c8-8fbe-4397-9dbb-9b2b20218538

BUG=181315
BUG=233866
TEST=WebFrameTest.pageScaleFactorUpdatesScrollbars (last reapplication), WebFrameTest.setPageScaleFactorBeforeFrameHasView (first reapplication), WebFrameTest.setPageScaleFactorWithOverlayScrollbarsDoesNotLayout, WebFrameTest.pageScaleFactorUpdatesScrollbars

Review URL: https://chromiumcodereview.appspot.com/14283020

git-svn-id: svn://svn.chromium.org/blink/trunk@149455 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix build break caused by r149455

TBR=dpranke,thakis

Review URL: https://codereview.chromium.org/14671002

git-svn-id: svn://svn.chromium.org/blink/trunk@149456 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Switch speech synthesis from compile-flag to runtime-flag.

BUG=171887

Review URL: https://chromiumcodereview.appspot.com/14466008

git-svn-id: svn://svn.chromium.org/blink/trunk@149457 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make /workers JS wrapped objects ScriptWrappable.

This gets binding integrity benefits for these classes.

BUG=236671

Review URL: https://chromiumcodereview.appspot.com/14567003

git-svn-id: svn://svn.chromium.org/blink/trunk@149458 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove SKIA_ON_MAC_CHROMIUM. It is the same as OS(DARWIN).

No intended behavior change.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/14642017

git-svn-id: svn://svn.chromium.org/blink/trunk@149459 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Reorder functions in AccessibilityRenderObject.

No functional changes. Reorders the functions in AccessibilityRenderObject.h
and AccessibilityRenderObject.cpp to match AccessibilityObject.h, and fixes
whitespace issues.

Feel free to leave comments on future reordering, but unless there are
glaring errors, let's commit this and keep refactoring in subsequent
changes.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/14618004

git-svn-id: svn://svn.chromium.org/blink/trunk@149460 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Split the code for generating the license block out into its own python module
I'm about to re-use this in a new script.  I don't know if we need
license blocks in generated code, but until I hear otherwise
(or have a LICENSE file to read directly) I have this module.
At least we'll only have one place to change when we figure out the
correct LICENSE rules.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/14568004

git-svn-id: svn://svn.chromium.org/blink/trunk@149461 bbb929c8-8fbe-4397-9dbb-9b2b20218538