Bug 164529 [FieldAssist] Provide the ability to listen to start and end field assist events
In the previous content assist functionality, an ICompletionListener could be specified to listen to the following events: public void assistSessionEnded(ContentAssistEvent event) public void assistSessionStarted(ContentAssistEvent event) The equivalent listener, IContentProposalListener, does not listen to those two events. PDE needs to know when an assist session is ended in order to reset the state it maintains for custom filtering of java type results. The current event does not handle the case where the user ends the content assist without selecting a proposal: public void proposalAccepted(IContentProposal proposal);
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
*/
	public IContentProposalProvider getContentProposalProvider() {
		return proposalProvider;
	}
	/**
	 * Set the content proposal provider that is used to show proposals.
	 * 
	 * @param proposalProvider
	 *            the {@link IContentProposalProvider} used to show proposals
	 */
	public void setContentProposalProvider(
			IContentProposalProvider proposalProvider) {
		this.proposalProvider = proposalProvider;
	}
	/**
	 * Return the array of characters on which the popup is autoactivated.
	 * 
	 * @return An array of characters that trigger auto-activation of content
	 *         proposal. If specified, these characters will trigger
	 *         auto-activation of the proposal popup, regardless of whether an
	 *         explicit invocation keyStroke was specified. If this parameter is
	 *         <code>null</code>, then only a specified keyStroke will invoke
	 *         content proposal. If this value is <code>null</code> and the
	 *         keyStroke value is <code>null</code>, then all alphanumeric
	 *         characters will auto-activate content proposal.
	 */
	public char[] getAutoActivationCharacters() {
		if (autoActivateString == null) {
			return null;
		}