fix(chips): default click action on chip being prevented (#12856)

Fixes all the click actions on a chip being prevented. The action wasn't being prevented up until c82aca9 where it got moved out of the `if (this.disabled)`. Since there isn't any info or tests around why it was done this way, I'm assuming that it was by accident.

Fixes #9032.

src/lib/chips/chip-list.ts

@@ -437,7 +437,11 @@ export class MatChipList extends _MatChipListMixinBase implements MatFormFieldCo
    * Implemented as part of MatFormFieldControl.
    * @docs-private
    */
-  onContainerClick() { this.focus(); }
+  onContainerClick(event: MouseEvent) {
+    if (!this._originatesFromChip(event)) {
+      this.focus();
+    }
+  }
 
   /**
    * Focuses the the first non-disabled chip in this chip list, or the associated input when there
@@ -739,4 +743,19 @@ export class MatChipList extends _MatChipListMixinBase implements MatFormFieldCo
       }
     });
   }
+
+  /** Checks whether an event comes from inside a chip element. */
+  private _originatesFromChip(event: Event): boolean {
+    let currentElement = event.target as HTMLElement | null;
+
+    while (currentElement && currentElement !== this._elementRef.nativeElement) {
+      if (currentElement.classList.contains('mat-chip')) {
+        return true;
+      }
+
+      currentElement = currentElement.parentElement;
+    }
+
+    return false;
+  }
 }

src/lib/chips/chip.spec.ts

@@ -1,6 +1,6 @@
 import {Directionality} from '@angular/cdk/bidi';
 import {BACKSPACE, DELETE, SPACE} from '@angular/cdk/keycodes';
-import {createKeyboardEvent} from '@angular/cdk/testing';
+import {createKeyboardEvent, dispatchFakeEvent} from '@angular/cdk/testing';
 import {Component, DebugElement} from '@angular/core';
 import {async, ComponentFixture, TestBed} from '@angular/core/testing';
 import {By} from '@angular/platform-browser';
@@ -132,6 +132,24 @@ describe('Chips', () => {
 
         expect(testComponent.chipRemove).toHaveBeenCalledWith({chip: chipInstance});
       });
+
+      it('should not prevent the default click action', () => {
+        const event = dispatchFakeEvent(chipNativeElement, 'click');
+        fixture.detectChanges();
+
+        expect(event.defaultPrevented).toBe(false);
+      });
+
+      it('should prevent the default click action when the chip is disabled', () => {
+        chipInstance.disabled = true;
+        fixture.detectChanges();
+
+        const event = dispatchFakeEvent(chipNativeElement, 'click');
+        fixture.detectChanges();
+
+        expect(event.defaultPrevented).toBe(true);
+      });
+
     });
 
     describe('keyboard behavior', () => {

src/lib/chips/chip.ts

@@ -326,15 +326,13 @@ export class MatChip extends _MatChipMixinBase implements FocusableOption, OnDes
     }
   }
 
-  /** Ensures events fire properly upon click. */
+  /** Handles click events on the chip. */
   _handleClick(event: Event) {
-    // Check disabled
     if (this.disabled) {
-      return;
+      event.preventDefault();
+    } else {
+      event.stopPropagation();
     }
-
-    event.preventDefault();
-    event.stopPropagation();
   }
 
   /** Handle custom key presses. */