fix(animations): retain styling when transition destinations are changed (#12208)

Closes #9661
Closes #12208

modules/@angular/core/src/animation/animation_group_player.ts

@@ -88,7 +88,7 @@ export class AnimationGroupPlayer implements AnimationPlayer {
     this._started = false;
   }
 
-  setPosition(p: any /** TODO #9100 */): void {
+  setPosition(p: number): void {
     this._players.forEach(player => { player.setPosition(p); });
   }
 
@@ -100,4 +100,6 @@ export class AnimationGroupPlayer implements AnimationPlayer {
     });
     return min;
   }
+
+  get players(): AnimationPlayer[] { return this._players; }
 }

modules/@angular/core/src/animation/animation_player.ts

@@ -56,6 +56,6 @@ export class NoOpAnimationPlayer implements AnimationPlayer {
   finish(): void { this._onFinish(); }
   destroy(): void {}
   reset(): void {}
-  setPosition(p: any /** TODO #9100 */): void {}
+  setPosition(p: number): void {}
   getPosition(): number { return 0; }
 }

modules/@angular/core/src/animation/animation_sequence_player.ts

@@ -104,7 +104,9 @@ export class AnimationSequencePlayer implements AnimationPlayer {
     }
   }
 
-  setPosition(p: any /** TODO #9100 */): void { this._players[0].setPosition(p); }
+  setPosition(p: number): void { this._players[0].setPosition(p); }
 
   getPosition(): number { return this._players[0].getPosition(); }
+
+  get players(): AnimationPlayer[] { return this._players; }
 }

modules/@angular/core/src/animation/animation_style_util.ts

@@ -84,6 +84,8 @@ export function balanceAnimationKeyframes(
     firstKeyframe.styles.styles.push(extraFirstKeyframeStyles);
   }
 
+  collectAndResolveStyles(collectedStyles, [finalStateStyles]);
+
   return keyframes;
 }
 

modules/@angular/core/src/debug/debug_renderer.ts

@@ -22,7 +22,7 @@ export class DebugDomRootRenderer implements RootRenderer {
   }
 }
 
-export class DebugDomRenderer implements Renderer {
+export class DebugDomRenderer {
   constructor(private _delegate: Renderer) {}
 
   selectRootElement(selectorOrNode: string|any, debugInfo?: RenderDebugInfo): any {
@@ -150,7 +150,9 @@ export class DebugDomRenderer implements Renderer {
 
   animate(
       element: any, startingStyles: AnimationStyles, keyframes: AnimationKeyframe[],
-      duration: number, delay: number, easing: string): AnimationPlayer {
-    return this._delegate.animate(element, startingStyles, keyframes, duration, delay, easing);
+      duration: number, delay: number, easing: string,
+      previousPlayers: AnimationPlayer[] = []): AnimationPlayer {
+    return this._delegate.animate(
+        element, startingStyles, keyframes, duration, delay, easing, previousPlayers);
   }
 }

modules/@angular/core/src/linker/animation_view_context.ts

@@ -8,8 +8,9 @@
 import {AnimationGroupPlayer} from '../animation/animation_group_player';
 import {AnimationPlayer} from '../animation/animation_player';
 import {queueAnimation as queueAnimationGlobally} from '../animation/animation_queue';
-import {AnimationTransitionEvent} from '../animation/animation_transition_event';
+import {AnimationSequencePlayer} from '../animation/animation_sequence_player';
 import {ViewAnimationMap} from '../animation/view_animation_map';
+import {ListWrapper} from '../facade/collection';
 
 export class AnimationViewContext {
   private _players = new ViewAnimationMap();
@@ -30,15 +31,26 @@ export class AnimationViewContext {
     this._players.set(element, animationName, player);
   }
 
-  cancelActiveAnimation(element: any, animationName: string, removeAllAnimations: boolean = false):
-      void {
+  getAnimationPlayers(element: any, animationName: string, removeAllAnimations: boolean = false):
+      AnimationPlayer[] {
+    const players: AnimationPlayer[] = [];
     if (removeAllAnimations) {
-      this._players.findAllPlayersByElement(element).forEach(player => player.destroy());
+      this._players.findAllPlayersByElement(element).forEach(
+          player => { _recursePlayers(player, players); });
     } else {
-      const player = this._players.find(element, animationName);
-      if (player) {
-        player.destroy();
+      const currentPlayer = this._players.find(element, animationName);
+      if (currentPlayer) {
+        _recursePlayers(currentPlayer, players);
       }
     }
+    return players;
+  }
+}
+
+function _recursePlayers(player: AnimationPlayer, collectedPlayers: AnimationPlayer[]) {
+  if ((player instanceof AnimationGroupPlayer) || (player instanceof AnimationSequencePlayer)) {
+    player.players.forEach(player => _recursePlayers(player, collectedPlayers));
+  } else {
+    collectedPlayers.push(player);
   }
 }

modules/@angular/core/src/render/api.ts

@@ -88,7 +88,8 @@ export abstract class Renderer {
 
   abstract animate(
       element: any, startingStyles: AnimationStyles, keyframes: AnimationKeyframe[],
-      duration: number, delay: number, easing: string): AnimationPlayer;
+      duration: number, delay: number, easing: string,
+      previousPlayers?: AnimationPlayer[]): AnimationPlayer;
 }
 
 /**