CCA: Minimze/Restore window when receiving onLaunched event

Currently we just drop the event when there is active window instance.
We should minimize/restore the active window when receiving onLaunched
event.

Bug: b/155027774
Test: Manually test
Change-Id: I41ddf53cfb439ad6b32ae628c35e271d709561eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2167739Reviewed-by: Kuo Jen Wei <inker@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Commit-Queue: Wei Lee <wtlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#763298}

chrome/browser/resources/chromeos/camera/src/js/background.js

@@ -269,6 +269,18 @@ class CCAWindow {
     this.state_ = WindowState.CLOSING;
     this.appWindow_.close();
   }
+
+  /**
+   * Minimize or restore the app window.
+   */
+  minimizeOrRestore() {
+    if (this.appWindow_.isMinimized()) {
+      this.appWindow_.restore();
+      this.appWindow_.focus();
+    } else {
+      this.appWindow_.minimize();
+    }
+  }
 }
 
 /**
@@ -416,6 +428,11 @@ class Background {
    */
   launchApp() {
     if (this.launcherWindow_ || this.intentWindow_) {
+      const activeWindow = [this.launcherWindow_, this.intentWindow_].find(
+          (wnd) => wnd !== null && wnd.state_ === WindowState.ACTIVE);
+      if (activeWindow !== undefined) {
+        activeWindow.minimizeOrRestore();
+      }
       return;
     }
     this.assert_(