Layer squashing causes incorrect rendering while scrolling in Gmail

RenderLayer::boundingBoxForCompositing knew how to exclude RenderLayers that
had their own composited layer mapping, but it didn't know how to exclude
RenderLayers that paint into grouped backings.

R=vollick@chromium.org
BUG=370667

Review URL: https://codereview.chromium.org/271863003

git-svn-id: svn://svn.chromium.org/blink/trunk@173653 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Support warning decorations in Timeline flame chart based on trace events

BUG=361045

Review URL: https://codereview.chromium.org/270553005

git-svn-id: svn://svn.chromium.org/blink/trunk@173654 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Build fix after r173654

The change https://codereview.chromium.org/270553005/ doesn't update
inspector.html after moving TracingModel.js. This breaks devtools_frontend_resources
target

BUG=361045
TBR=yurys@chromium.org

Review URL: https://codereview.chromium.org/267363011

git-svn-id: svn://svn.chromium.org/blink/trunk@173655 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Timeline: make frames in TimelineView selectable

- generalize selection in timeline, so we can select multiple
    types of objects (currently, just records and frames);
- make frame bars in the top of classic Timeline view selectable
(mutually exclusive with selected records on the left);
- move contents of frame details popover into details view;

BUG=

Review URL: https://codereview.chromium.org/270693003

git-svn-id: svn://svn.chromium.org/blink/trunk@173656 bbb929c8-8fbe-4397-9dbb-9b2b20218538