Add support for IconButton.

Author: Piotr Siatka

src/controls/filePicker/FilePicker.tsx

@@ -3,7 +3,7 @@ import { IFilePickerProps } from './IFilePickerProps';
 import { IFilePickerState } from './IFilePickerState';
 
 // Office Fabric controls
-import { PrimaryButton } from 'office-ui-fabric-react/lib/components/Button';
+import { PrimaryButton, IconButton } from 'office-ui-fabric-react/lib/components/Button';
 import { Panel, PanelType } from 'office-ui-fabric-react/lib/components/Panel';
 import { Label } from 'office-ui-fabric-react/lib/components/Label';
 import { Nav, INavLink, INavLinkGroup } from 'office-ui-fabric-react/lib/Nav';
@@ -70,13 +70,21 @@ export class FilePicker extends React.Component<IFilePickerProps, IFilePickerSta
       onClose: () => this._handleClosePanel(),
       onSave: (value: IFilePickerResult) => { this._handleSave(value); }
     };
+    const buttonProps = {
+      disabled: this.props.disabled,
+      onClick: this._handleOpenPanel
+    }
 
     return (
       <div >
-        <Label required={this.props.required}>{this.props.label}</Label>
-        <PrimaryButton text={this.props.buttonLabel}
-          onClick={this._handleOpenPanel}
-          disabled={this.props.disabled} />
+        {
+          this.props.label && <Label required={this.props.required}>{this.props.label}</Label>
+        }
+        {
+          this.props.buttonIcon ?
+            <IconButton iconProps={{ iconName: this.props.buttonIcon }} {...buttonProps} /> :
+            <PrimaryButton text={this.props.buttonLabel} {...buttonProps}/>
+        }
 
         <Panel isOpen={this.state.panelOpen}
           isBlocking={true}

src/controls/filePicker/IFilePickerProps.ts

@@ -9,7 +9,12 @@ export interface IFilePickerProps {
   /**
    * Specifies the label of the file picker button
    */
-  buttonLabel: string;
+  buttonLabel?: string;
+
+  /**
+   * Specifies the icon to be used to display Icon Button.
+   */
+  buttonIcon?: string;
 
   /**
    * Content of the file.

src/webparts/controlsTest/components/ControlsTest.tsx

@@ -340,8 +340,9 @@ export default class ControlsTest extends React.Component<IControlsTestProps, IC
       <div className={styles.controlsTest}>
         <FilePicker
           bingAPIKey="D41D8CD98F00B204E9800998ECF8427E06193A4E"
-          buttonLabel="Choose file"
-          label="File picker"
+          // buttonLabel="Choose file"
+          // label="File picker"
+          buttonIcon="FileImage"
           onSave={(filePickerResult: IFilePickerResult) => { this.setState({filePickerResult }) }}
           onChanged={(filePickerResult: IFilePickerResult) => { this.setState({filePickerResult }) }}
           filePickerResult={null}