DevTools: add more logging to console-viewport-selection.html

The patch adds more logging to the console-viewport-selection.html test
to figure out possible source of its flakiness.

BUG=390204
TBR=vsevik

Review URL: https://codereview.chromium.org/392643002

git-svn-id: svn://svn.chromium.org/blink/trunk@178070 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use reference for FillLayer if possible

RenderStyle::backgroundBackgroundLayers() and maskLayers() always
return non-null FillLayer, so we can reference for them.

Also changed accessBackgroundLayers() and accessMaskLayers().

Also changed callers and some callers of callers of the functions.

Review URL: https://codereview.chromium.org/381473002

git-svn-id: svn://svn.chromium.org/blink/trunk@178071 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: refactoring connection creation, removing a couple of dead code branches.

NOTRY=true

Review URL: https://codereview.chromium.org/392603002

git-svn-id: svn://svn.chromium.org/blink/trunk@178072 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Get rid of WebInspector.TargetObserver

BUG=

Review URL: https://codereview.chromium.org/388303002

git-svn-id: svn://svn.chromium.org/blink/trunk@178073 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert of DevTools: fixed compilation problem with InjectedScriptSource.js (https://chromiumcodereview.appspot.com/390853002/)

Reason for revert:
The original patch that was fixed by this one was reverted.

Original issue's description:
> Added declarations to InjectedScriptExterns:
> JavaScriptCallFrame.prototype.evaluateWithExceptionDetails = function(expression) { }
> InjectedScriptHostClass.prototype.eval = function(expression) 
> InjectedScriptHostClass.prototype.evaluateWithExceptionDetails = function(expression) { }
> These methods was added in https://codereview.chromium.org/289423002/
> 
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178059

TBR=pfeldman@chromium.org,kozyatinskiy@google.com
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/388253005

git-svn-id: svn://svn.chromium.org/blink/trunk@178074 bbb929c8-8fbe-4397-9dbb-9b2b20218538