fix(autocomplete): unable to click to select items in IE

* Fixes being unable to select autocomplete items by clicking in IE. This was due to IE not setting the `event.relatedTarget` for blur events.
* Fixes potential issue if the user uses `mat-option`, instead of `md-option`.

Author: crisbeto

src/lib/autocomplete/autocomplete-trigger.ts

@@ -60,8 +60,8 @@ export const MD_AUTOCOMPLETE_VALUE_ACCESSOR: any = {
     '[attr.aria-expanded]': 'panelOpen.toString()',
     '[attr.aria-owns]': 'autocomplete?.id',
     '(focus)': 'openPanel()',
-    '(blur)': '_handleBlur($event.relatedTarget?.tagName)',
     '(input)': '_handleInput($event)',
+    '(focusout)': '_handleFocusOut($event)',
     '(keydown)': '_handleKeydown($event)',
   },
   providers: [MD_AUTOCOMPLETE_VALUE_ACCESSOR]
@@ -223,11 +223,17 @@ export class MdAutocompleteTrigger implements AfterContentInit, ControlValueAcce
     }
   }
 
-  _handleBlur(newlyFocusedTag: string): void {
+  /**
+   * Handles the input element losing focus. Note that this should be handled on `focusout`,
+   * instead of `blur`, because IE doesn't set the `relatedTarget` for blur events.
+   */
+  _handleFocusOut(event: FocusEvent): void {
+    const relatedTarget = event.relatedTarget as HTMLElement;
+
     this._onTouched();
 
-    // Only emit blur event if the new focus is *not* on an option.
-    if (newlyFocusedTag !== 'MD-OPTION') {
+    // Only emit blur event if the new focus is *not* on an element inside the panel.
+    if (relatedTarget && !this._overlayRef.overlayElement.contains(relatedTarget)) {
       this._blurStream.next(null);
     }
   }

src/lib/autocomplete/autocomplete.spec.ts

@@ -92,7 +92,7 @@ describe('MdAutocomplete', () => {
       fixture.detectChanges();
 
       fixture.whenStable().then(() => {
-        dispatchEvent('blur', input);
+        dispatchEvent('focusout', input);
         fixture.detectChanges();
 
         expect(fixture.componentInstance.trigger.panelOpen)
@@ -423,7 +423,7 @@ describe('MdAutocomplete', () => {
       expect(fixture.componentInstance.stateCtrl.touched)
           .toBe(false, `Expected control to start out untouched.`);
 
-      dispatchEvent('blur', input);
+      dispatchEvent('focusout', input);
       fixture.detectChanges();
 
       expect(fixture.componentInstance.stateCtrl.touched)