DevTools: [CodeMirror] use Tab to accept autocompletion

This patch adds a functionality to commit autocomplete suggestion via
Tab key.

BUG=261560

Review URL: https://chromiumcodereview.appspot.com/19558004

git-svn-id: svn://svn.chromium.org/blink/trunk@154573 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add preprocessor to reloadOptions in chrome.devtools.inspectedWindow.reload().

Add options.preprocessor to ExtensionServer.js and
provide a default empty string value.

Add test case to extensions-reload.html to verify preprocessingScript is
run.

BUG=229971

Review URL: https://chromiumcodereview.appspot.com/13816005

git-svn-id: svn://svn.chromium.org/blink/trunk@154574 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert 154557 "Move runin to original position when sibling elem..."

Major security regression on ClusterFuzz. Causing use-after-frees.

> Move runin to original position when sibling element is destroyed. Additionally, if If moveRunInUnderSiblingBlockIfNeeded is called when the sibling run-in block is being destroyed, it means that the run-in is moving to original position and we do not need to do nothing.
> 
> R=
> BUG=260388
> 
> Review URL: https://chromiumcodereview.appspot.com/19290002

TBR=igor.o@sisa.samsung.com

Review URL: https://codereview.chromium.org/19569010

git-svn-id: svn://svn.chromium.org/blink/trunk@154575 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert "Reland change to enable deferred image decoding for animated GIFs"

Lots of image diffs showed up on http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=virtual%2Fdeferred%2Ffast%2Fimages%2Fwebp-color-profile-lossy.html

This reverts commit 4110425f5132d8d6f94395799c2d901068e38f6e.

TBR=hclam@chromium.org
BUG=169377,259786,259783

Review URL: https://codereview.chromium.org/19504009

git-svn-id: svn://svn.chromium.org/blink/trunk@154576 bbb929c8-8fbe-4397-9dbb-9b2b20218538