DevTools: normalize the onResize/doResize usage, drive-by sidebar scroller fix.

R=dgozman@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=165941

Review URL: https://codereview.chromium.org/137143016

git-svn-id: svn://svn.chromium.org/blink/trunk@166008 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Blocks that create a new block formatting context are not self-collapsing.

Per http://www.w3.org/TR/CSS2/box.html#collapsing-margins the top and bottom margins of a block that has no content and otherwise no height of its own can only collapse together if the box doesn't establish a block formatting context.

We already have a function that detects when a block is creating a new block formatting context, so rename it and use it to detect when we shouldn't collapse margins.

The newly renamed 'createsNewBlockFormattingContext' function needs to learn about other situations that create block formatting contexts (such as column-spans and regions) but that will be done in separate patches.

BUG=321295

Review URL: https://codereview.chromium.org/144213004

git-svn-id: svn://svn.chromium.org/blink/trunk@166009 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: fix inspector/extensions/extensions-sidebar.html

TBR=caseq
BUG=338752

Review URL: https://codereview.chromium.org/145123006

git-svn-id: svn://svn.chromium.org/blink/trunk@166010 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove redundant code for setting perspective transform

perspectiveTransform() already returns the identity matrix
when there is no perspective, so no need to avoid calling it.
Also, as far as I can tell clearing the transform on the graphics
layer is always OK when setting the clipLayer transform.

BUG=338896

Review URL: https://codereview.chromium.org/131003008

git-svn-id: svn://svn.chromium.org/blink/trunk@166011 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove vestigial code left over from prior cleanup.

There used to be an || condition on the outer if statement so it was possible
to enter the if with viewHasCompostedLayer set to true. The || portion of the
if was removed so, if we're inside the block then we know that
viewHasCompostedLayer is false. Which means, we never execute the inner if
statement.

Review URL: https://codereview.chromium.org/149263003

git-svn-id: svn://svn.chromium.org/blink/trunk@166012 bbb929c8-8fbe-4397-9dbb-9b2b20218538