Fix leak of inspectorClient when INSPECTOR disabled

WebKit PageClient api has undefined memory management. It seems
to take custody of the parameters only if it wants to use it.
Thus, only allocate inspectorClient if needed.

Change-Id: Ibae7e683ec0c9553845c482b52dab7fad94e4398
WebViewCore destructor must delete m_textFieldInitDataGlue

There was a memory leak detected in processes using webkit.
Investigation showed that it was the TextFieldInitDataGlue
object created in WebViewCore constructor.

Change-Id: I86a11f99f13aca6ab990627a9106c9e9b781edee