Split out InterActiveAuthDialog

Into a component that does Interactive Auth and a dialog that
wraps it, so we can do interactive auth not necessarily in a
dialog.

As a side effect:
 * Put the buttons for each auth stage in the stage itself.
   Some stages don't have submit buttons (and it's very possible
   other stages may have other buttons entirely, like 'resend')
   so it makes more sense for the buttons to live in the stage
   components themselves. Plus it saves the slightly evil
   calling-functions-on-react-children thing we were doing (and
   indeed extending that to show the submit button at all).
 * Give all BaseDialogs a cross in the top right to cancel. They
   were all dismissable by clicking outside or pressing esc, so
   this adds a more visually obvious way of dismissing them. Plus,
   it means our InteractiveAuthDialog can have a way of canceling
   the whole operation separate from buttons for the individual
   stages.

src/components/views/login/InteractiveAuthEntryComponents.js

@@ -32,7 +32,6 @@ import MatrixClientPeg from '../../../MatrixClientPeg';
  * stageParams:            params from the server for the stage being attempted
  * errorText:              error message from a previous attempt to authenticate
  * submitAuthDict:         a function which will be called with the new auth dict
- * setSubmitButtonEnabled: a function which will enable/disable the 'submit' button
  *
  * Each component may also provide the following functions (beyond the standard React ones):
  *    onSubmitClick: handle a 'submit' button click
@@ -48,12 +47,13 @@ export const PasswordAuthEntry = React.createClass({
 
     propTypes: {
         submitAuthDict: React.PropTypes.func.isRequired,
-        setSubmitButtonEnabled: React.PropTypes.func.isRequired,
         errorText: React.PropTypes.string,
     },
 
-    componentWillMount: function() {
-        this.props.setSubmitButtonEnabled(false);
+    getInitialState: function() {
+        return {
+            enableSubmit: false,
+        };
     },
 
     focus: function() {
@@ -62,7 +62,7 @@ export const PasswordAuthEntry = React.createClass({
         }
     },
 
-    onSubmitClick: function() {
+    _onSubmit: function() {
         this.props.submitAuthDict({
             type: PasswordAuthEntry.LOGIN_TYPE,
             user: MatrixClientPeg.get().credentials.userId,
@@ -72,7 +72,9 @@ export const PasswordAuthEntry = React.createClass({
 
     _onPasswordFieldChange: function(ev) {
         // enable the submit button iff the password is non-empty
-        this.props.setSubmitButtonEnabled(Boolean(ev.target.value));
+        this.setState({
+            enableSubmit: Boolean(this.refs.passwordField.value),
+        });
     },
 
     render: function() {
@@ -86,12 +88,20 @@ export const PasswordAuthEntry = React.createClass({
             <div>
                 <p>To continue, please enter your password.</p>
                 <p>Password:</p>
-                <input
-                    ref="passwordField"
-                    className={passwordBoxClass}
-                    onChange={this._onPasswordFieldChange}
-                    type="password"
-                />
+                <form onSubmit={this._onSubmit}>
+                    <input
+                        ref="passwordField"
+                        className={passwordBoxClass}
+                        onChange={this._onPasswordFieldChange}
+                        type="password"
+                    />
+                    <div className="mx_button_row">
+                        <input type="submit"
+                            className="mx_Dialog_primary"
+                            disabled={!this.state.enableSubmit}
+                        />
+                    </div>
+                </form>
                 <div className="error">
                     {this.props.errorText}
                 </div>
@@ -110,14 +120,9 @@ export const RecaptchaAuthEntry = React.createClass({
     propTypes: {
         submitAuthDict: React.PropTypes.func.isRequired,
         stageParams: React.PropTypes.object.isRequired,
-        setSubmitButtonEnabled: React.PropTypes.func.isRequired,
         errorText: React.PropTypes.string,
     },
 
-    componentWillMount: function() {
-        this.props.setSubmitButtonEnabled(false);
-    },
-
     _onCaptchaResponse: function(response) {
         this.props.submitAuthDict({
             type: RecaptchaAuthEntry.LOGIN_TYPE,
@@ -148,7 +153,6 @@ export const FallbackAuthEntry = React.createClass({
         authSessionId: React.PropTypes.string.isRequired,
         loginType: React.PropTypes.string.isRequired,
         submitAuthDict: React.PropTypes.func.isRequired,
-        setSubmitButtonEnabled: React.PropTypes.func.isRequired,
         errorText: React.PropTypes.string,
     },
 
@@ -156,7 +160,6 @@ export const FallbackAuthEntry = React.createClass({
         // we have to make the user click a button, as browsers will block
         // the popup if we open it immediately.
         this._popupWindow = null;
-        this.props.setSubmitButtonEnabled(true);
         window.addEventListener("message", this._onReceiveMessage);
     },
 
@@ -173,7 +176,6 @@ export const FallbackAuthEntry = React.createClass({
             this.props.authSessionId
         );
         this._popupWindow = window.open(url);
-        this.props.setSubmitButtonEnabled(false);
     },
 
     _onReceiveMessage: function(event) {