Prevent spinning up a layer tree view after closing

Prevent spinning up a layer tree view after closing

This patch is a prerequisite for
https://codereview.chromium.org/134623005/ which makes output surface
creation asynchronous.  In that patch, to prevent races between
asynchronously closing the RenderWidgetHost and creating an output
surface (which can't succeed if the host goes away), it destroys the
layer tree view during RenderWidget::DoDeferredClose/closeWidgetSoon.

Unfortunately, this causes issues in WebViewImpl which wants to assert
that it has a layer tree view in all cases (except where null layer tree
views are allowed).  To prevent this, don't let accelerated compositing
spin up (again, or for the first time) after the layer tree view has
been closed.

BUG=none

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177424

[enne (OOO), 2014-07-02 19:26:56]

jamesr, what do you think of this? This is the Blink side of the change to fix
issues like:

ASSERTION FAILED: m_client->allowsBrokenNullLayerTreeView()
../../third_party/WebKit/Source/web/WebViewImpl.cpp(3966) : void
blink::WebViewImpl::setIsAcceleratedCompositingActive(bool)
Received signal 11 SEGV_MAPERR 0000fbadbeef
#0 0x7f5d4291b7ce base::debug::StackTrace::StackTrace()
#1 0x7f5d4291b307 base::debug::(anonymous namespace)::StackDumpSignalHandler()
#2 0x7f5d33975cb0 <unknown>
#3 0x7f5d37f24b49 blink::WebViewImpl::setIsAcceleratedCompositingActive()
#4 0x7f5d37f29eff blink::WebViewImpl::setRootGraphicsLayer()
#5 0x7f5d37e14561 blink::ChromeClientImpl::attachRootGraphicsLayer()
#6 0x7f5d3a13bacc WebCore::RenderLayerCompositor::attachRootLayer()
#7 0x7f5d3a1387aa WebCore::RenderLayerCompositor::ensureRootLayer()
#8 0x7f5d3a138226 WebCore::RenderLayerCompositor::setCompositingModeEnabled()
#9 0x7f5d3a138ddc
WebCore::RenderLayerCompositor::enableCompositingModeIfNeeded()
#10 0x7f5d3a139b2d WebCore::RenderLayerCompositor::didLayout()
#11 0x7f5d39c51df7 WebCore::FrameView::layout()
#12 0x7f5d39c56563 WebCore::FrameView::scrollbarExistenceDidChange()
#13 0x7f5d43bf8199 WebCore::ScrollView::adjustScrollbarExistence()
#14 0x7f5d43bf609f WebCore::ScrollView::updateScrollbars()
#15 0x7f5d43bf6982 WebCore::ScrollView::setContentsSize()
#16 0x7f5d39c4f13e WebCore::FrameView::setContentsSize()
#17 0x7f5d39c4f4e6 WebCore::FrameView::adjustViewSize()
#18 0x7f5d39c51d5c WebCore::FrameView::layout()
#19 0x7f5d3941eff1 WebCore::Document::implicitClose()
#20 0x7f5d39de5874 WebCore::FrameLoader::checkCompleted()
#21 0x7f5d39de42fd WebCore::FrameLoader::finishedParsing()
#22 0x7f5d3942a196 WebCore::Document::finishedParsing()
#23 0x7f5d3984c471 WebCore::HTMLConstructionSite::finishedParsing()
#24 0x7f5d3989d2e9 WebCore::HTMLTreeBuilder::finished()
#25 0x7f5d3985a08a WebCore::HTMLDocumentParser::end()
#26 0x7f5d398555d0
WebCore::HTMLDocumentParser::attemptToRunDeferredScriptsAndEnd()
#27 0x7f5d3985530c WebCore::HTMLDocumentParser::prepareToStopParsing()
#28 0x7f5d39858675
WebCore::HTMLDocumentParser::processParsedChunkFromBackgroundParser()
#29 0x7f5d39856b80 WebCore::HTMLDocumentParser::pumpPendingSpeculations()
#30 0x7f5d39857404
WebCore::HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser()
#31 0x7f5d3984229e WTF::FunctionWrapper<>::operator()()
#32 0x7f5d398421c7 WTF::BoundFunctionImpl<>::operator()()
#33 0x7f5d32567183 WTF::Function<>::operator()()
#34 0x7f5d32566f5d WTF::callFunctionObject()
#35 0x7f5d3c901c8d base::internal::RunnableAdapter<>::Run()
#36 0x7f5d3c901c55 base::internal::InvokeHelper<>::MakeItSo()
#37 0x7f5d3c901c29 base::internal::Invoker<>::Run()
#38 0x7f5d429041ce base::Callback<>::Run()

[jamesr, 2014-07-02 19:31:50]

lgtm

[enne (OOO), 2014-07-02 21:14:29]

The CQ bit was checked by enne@chromium.org

[commit-bot: I haz the power, 2014-07-02 21:14:59]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/enne@chromium.org/362403003/1

[commit-bot: I haz the power, 2014-07-02 21:19:13]

Change committed as 177424