linux/mac: Fix return status of OpenChannelToPlugin message in case of failure
linux/mac: Fix return status of OpenChannelToPlugin message in case of failure

Currently on linux if the plugin process dies, the PluginProcessHost is not destroyed.
A side effect of that is that if a renderer tries to create a new plugin, the OpenChannelToPlugin message returns success with an empty handle, which is interpreted as the host channel, to which the renderer tries to connect to a second time, causing DCHECKs and havok in the browser process.
This CL fixes that particular problem, returning failure if the browser can't connect to the plugin process.

Review URL: http://codereview.chromium.org/155313


git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@20337 0039d316-1c4b-4281-b951-d872f2087c98

Crystalnix/house-of-life-chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,adobe/chromium