DevTools: Freshen up popover styles.

Drop the aging yellow popover and match the tooltip style in Chrome.

TBR=sergeyv
BUG=181703

Review URL: https://codereview.chromium.org/401013002

git-svn-id: svn://svn.chromium.org/blink/trunk@178466 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move RenderBlockFlow::constructTextRun out.

It doesn't need anything particular to block flows, and is used by other
kinds of renderers.

Review URL: https://codereview.chromium.org/397723006

git-svn-id: svn://svn.chromium.org/blink/trunk@178467 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move widow-avoiding code from RenderBlock down to RenderBlockFlow.

BUG=302024

Review URL: https://codereview.chromium.org/399423006

git-svn-id: svn://svn.chromium.org/blink/trunk@178468 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename FontPlatformDataLinuxHarfBuzz to FontPlatformDataLinux

Rename the linux specific FontPlatformData implementation file from
FontPlatformDataLinuxHarfBuzz.cpp to FontPlatformDataLinux.cpp as all
platforms use HarfBuzz now.

R=jbroman@chromium.org

Review URL: https://codereview.chromium.org/404653004

git-svn-id: svn://svn.chromium.org/blink/trunk@178469 bbb929c8-8fbe-4397-9dbb-9b2b20218538