DevTools: Speedup CPU profile model frames iterator.

The speedup is about 10x.

Review URL: https://codereview.chromium.org/253143003

git-svn-id: svn://svn.chromium.org/blink/trunk@172962 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Support loading old CPU profiles (ones w/o timestamps)

Review URL: https://codereview.chromium.org/257223002

git-svn-id: svn://svn.chromium.org/blink/trunk@172963 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add tabindex handling in svg, by reusing code from html.

Besides adding the tabindex attribute also reflect it to the tabIndex IDL attribute on the SVGElement interface.

Spec: https://svgwg.org/svg2-draft/interact.html#sequential-focus-navigation-and-the-tabindex-attribute
IDL attribute: https://svgwg.org/svg2-draft/types.html#__svg__SVGElement__tabIndex

BUG=352175

Review URL: https://codereview.chromium.org/166163005

git-svn-id: svn://svn.chromium.org/blink/trunk@172964 bbb929c8-8fbe-4397-9dbb-9b2b20218538
activation-after-registration.html is no longer flaky

Fixed in Chromium r266544 <https://codereview.chromium.org/255813003/>

BUG=365252

Review URL: https://codereview.chromium.org/262493003

git-svn-id: svn://svn.chromium.org/blink/trunk@172965 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[oilpan]: Remove some of the simpler persistents in the node hierarchy.

Also decided to move HTMLElementEquivalents and subclasses to the heap to get rid of some persistents.

R=ager@chromium.org, erik.corry@gmail.com, haraken@chromium.org, oilpan-reviews@chromium.org, tkent@chromium.org, vegorov@chromium.org, zerny@chromium.org
BUG=341815

Review URL: https://codereview.chromium.org/256063005

git-svn-id: svn://svn.chromium.org/blink/trunk@172966 bbb929c8-8fbe-4397-9dbb-9b2b20218538