Only use devtools category for devtools instrumentation trace events

- change PlatformInstrumentation events to use "devtools" as category
- change category filter to only include "devtools"

BUG=
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/180783016

git-svn-id: svn://svn.chromium.org/blink/trunk@169445 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Drop Element::isHTMLFrameElementBase() virtual function

Drop Element::isHTMLFrameElementBase() virtual function and have
isHTMLFrameElementBase() helper use the isHTML*Element() helpers instead.
This is more consistent with other HTML Elements and simplifies the code
a little bit.

R=tkent, adamk
BUG=346095

Review URL: https://codereview.chromium.org/197873022

git-svn-id: svn://svn.chromium.org/blink/trunk@169446 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Initialise raw pointer to null in FontBuilder constructor

RenderStyle* m_style on FontBuilder doesn't get initialised in the
constructor. The majority of methods on FontBuilder will attempt to deref
it as a garbage raw pointer if they get called before initForStyleResolve()
is called.

Review URL: https://codereview.chromium.org/197883021

git-svn-id: svn://svn.chromium.org/blink/trunk@169447 bbb929c8-8fbe-4397-9dbb-9b2b20218538