DevTools: make console.timeline/timelineEnd work for tracing based Timeline

* console.timeline/timelineEnd doesn't start/stop timeline recording when tracing backend is used, instead they will result in a pair of blink.console async events similar to console.time/timeEnd. This will allow to easily select corresponding interval on the recorded timeline.

* console.timeline/timelineEnd will produce deprecation warnings in the console. The users should start using console.time/timeEnd instead.

BUG=412782

Review URL: https://codereview.chromium.org/593123003

git-svn-id: svn://svn.chromium.org/blink/trunk@182511 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Inline exception handling code into PrivateScriptRunner helpers

Inline the v8::TryCatch and rethrowExceptionInPrivateScript() call into
PrivateScriptRunner's runDOMAttributeGetter(), runDOMAttributeSetter()
and runDOMMethod().

This is done to avoid duplicating the code once per actual attribute
getter/setter callback or method callback.

BUG=

Review URL: https://codereview.chromium.org/594213002

git-svn-id: svn://svn.chromium.org/blink/trunk@182512 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove inclusion of WebImageLayer.h from ImageLayerChromiumTest.cpp

This is unused header in the given test.

Review URL: https://codereview.chromium.org/592383003

git-svn-id: svn://svn.chromium.org/blink/trunk@182513 bbb929c8-8fbe-4397-9dbb-9b2b20218538