Defer to generate breakpad symbols to decide whether or not to dump symbols

When using shared libraries, the main binary might not have been touched
even if one of the dependencies was updated.

BUG=369608
R=dpranke@chromium.org

Review URL: https://codereview.chromium.org/276433002

git-svn-id: svn://svn.chromium.org/blink/trunk@173544 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Create an antialiased virtual layout test group for font testing on Mac.

BUG=367088

Review URL: https://codereview.chromium.org/249343002

git-svn-id: svn://svn.chromium.org/blink/trunk@173545 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add blink-side plumbing for ServiceWorker -> Document postMessage

- Initialize NavigatorServiceWorker and ServiceWorkerContainer earlier, right after a document is available (for Documents)
- Add public interfaces:
-- WebServiceWorkerContextClient.postMessageToClient()
-- WebServiceWorkerProviderClient.dispatchMessageEvent()

This is the first patch for postMessage plumbing: 
1/3: THIS PATCH
2/3: https://codereview.chromium.org/246023007/ (chromium) 
3/3: https://codereview.chromium.org/264233003/ (blink, adds Layout test)

BUG=366063
TEST=to be added after chromium-side change is landed

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=173495

Review URL: https://codereview.chromium.org/263143004

git-svn-id: svn://svn.chromium.org/blink/trunk@173546 bbb929c8-8fbe-4397-9dbb-9b2b20218538