WebUI Tabstrip: Add JS type checking for test_tabs_api_proxy.js

Split TabsApiProxy (class) to
TabsApiProxy (interface) + TabsApiProxyImpl (class), so that
TestTabsApiProxy can implement the same interface.

Also adding placeholder js_type_check() targets for the remaining
tab_strip/ Mocha test files.

This is done to facilitate the parallelization of the effort to add JS
type checking for WebUI tests. It makes it easier to see which parts of
the code are not type checked yet.

Bug: 1000989
Change-Id: Ida2acf4fcecd75e59f8266f0d1f2abb2040bd625
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2202942
Auto-Submit: dpapad <[email protected]>
Commit-Queue: John Lee <[email protected]>
Reviewed-by: John Lee <[email protected]>
Cr-Commit-Position: refs/heads/master@{#769312}
diff --git a/chrome/browser/resources/tab_strip/tab.js b/chrome/browser/resources/tab_strip/tab.js
index 4c6fbb9..db8fee45 100644
--- a/chrome/browser/resources/tab_strip/tab.js
+++ b/chrome/browser/resources/tab_strip/tab.js
@@ -14,7 +14,7 @@
 import {TabStripEmbedderProxy} from './tab_strip_embedder_proxy.js';
 import {tabStripOptions} from './tab_strip_options.js';
 import {TabSwiper} from './tab_swiper.js';
-import {CloseTabAction, TabData, TabNetworkState, TabsApiProxy} from './tabs_api_proxy.js';
+import {CloseTabAction, TabData, TabNetworkState, TabsApiProxy, TabsApiProxyImpl} from './tabs_api_proxy.js';
 
 const DEFAULT_ANIMATION_DURATION = 125;
 
@@ -84,7 +84,7 @@
     this.tab_;
 
     /** @private {!TabsApiProxy} */
-    this.tabsApi_ = TabsApiProxy.getInstance();
+    this.tabsApi_ = TabsApiProxyImpl.getInstance();
 
     /** @private {!TabStripEmbedderProxy} */
     this.embedderApi_ = TabStripEmbedderProxy.getInstance();