<http://webkit.org/b/86143>
<rdar://problem/10777218>

Reviewed by Anders Carlsson.

To avoid spins beneath PluginInfoStore::getPluginInfo(), do this work on a secondary
thread in the UIProcess.

* Shared/APIObject.h:

    Made APIObject a ThreadSafeRefCounted. In the context of this patch, this is to
    be able to dispatch bound Functions on WebContext.

* WebProcess/mac/KeychainItemShimMethods.mm:
(WebKit::responseMap):
* WebProcess/mac/SecItemShimMethods.mm:
(WebKit::responseMap):
* WebKit2.xcodeproj/project.pbxproj:
* Shared/BlockingResponseMap.h:
(BlockingResponseMap):
(BlockingResponseMap::waitForResponse):
(BlockingResponseMap::didReceiveResponse):

     Renamed from Source/WebKit2/WebProcess/mac/KeychainShimResponseMap.h.
     Generalize this somewhat since it's useful in more than just the keychain scenario.
     This can/should be generalized further, but that's a topic for another patch.

* UIProcess/Plugins/PluginInfoStore.h:
* UIProcess/Plugins/PluginInfoStore.cpp:
(WebKit::PluginInfoStore::plugins):
(WebKit::PluginInfoStore::findPluginForMIMEType):
(WebKit::PluginInfoStore::findPluginForExtension):
(WebKit::PluginInfoStore::findPlugin):
(WebKit::PluginInfoStore::infoForPluginWithPath):

    Slap a mutex on the PluginInfoStore since it can now be called from both the
    main thread (via WKFrameCanShowMIMEType) and the GetPlugin work queue.

* UIProcess/WebContext.messages.in:
* UIProcess/WebContext.h:
* UIProcess/WebContext.cpp:
(WebKit::WebContext::WebContext):
(WebKit::WebContext::~WebContext):
(WebKit::WebContext::processDidFinishLaunching):
(WebKit::WebContext::sendDidGetPlugins):
(WebKit::WebContext::handleGetPlugins):
(WebKit::WebContext::getPlugins):
(WebKit::WebContext::didReceiveMessageOnConnectionWorkQueue):

    Make GetPlugins a DispatchOnConnectionQueue message and execute it on a new
    plug-in work queue. This effectively makes the GetPlugin call asynchronous.
    On Mac, the built-in PDF reader is still registered on the main thread as that
    ends up calling into localizedString().

* WebProcess/WebProcess.cpp:
(WebKit::WebProcess::didGetPlugins):
* WebProcess/WebProcess.h:
* WebProcess/WebProcess.messages.in:

    Add a DidGetPlugins message to WebProcess. This is passed directly to the handler
    in WebPlatformStrategies.cpp.

* WebProcess/WebCoreSupport/WebPlatformStrategies.h:
* WebProcess/WebCoreSupport/WebPlatformStrategies.cpp:
(WebKit::responseMap):
(WebKit::handleDidGetPlugins):
(WebKit::generateRequestID):
(WebKit::WebPlatformStrategies::populatePluginCache):

    Use a BlockingResponseMap to block the WebProcess main thread until the UIProcess
    responds with DidGetPlugins.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@116796 268f45cc-cd09-0410-ab3c-d52691b4dbfc