[Messages] Fix queue is incorrectly suspended after tab switching

Queue should be resumed right after browsing mode is visible.

Bug: 1156113
Change-Id: Idedadb8662249bcd1e655e939b1f23a93323dd4d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2586273Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Pavel Yatsuk <pavely@chromium.org>
Commit-Queue: Lijin Shen <lazzzis@google.com>
Cr-Commit-Position: refs/heads/master@{#835960}

chrome/android/java/src/org/chromium/chrome/browser/messages/ChromeMessageQueueMediator.java

@@ -57,15 +57,16 @@ public class ChromeMessageQueueMediator implements MessageQueueDelegate {
     private LayoutStateObserver mLayoutStateObserver = new LayoutStateObserver() {
         private int mToken = TokenHolder.INVALID_TOKEN;
 
+        // Suspend the queue until browsing mode is visible.
         @Override
-        public void onStartedShowing(int layoutType, boolean showToolbar) {
+        public void onStartedShowing(@LayoutType int layoutType, boolean showToolbar) {
             if (mToken == TokenHolder.INVALID_TOKEN && layoutType != LayoutType.BROWSING) {
                 mToken = suspendQueue();
             }
         }
 
         @Override
-        public void onFinishedHiding(int layoutType) {
+        public void onFinishedShowing(@LayoutType int layoutType) {
             if (mToken != TokenHolder.INVALID_TOKEN && layoutType == LayoutType.BROWSING) {
                 resumeQueue(mToken);
                 mToken = TokenHolder.INVALID_TOKEN;

chrome/android/junit/src/org/chromium/chrome/browser/messages/ChromeMessageQueueMediatorTest.java

@@ -106,7 +106,7 @@ public class ChromeMessageQueueMediatorTest {
         doNothing().when(mLayoutStateProvider).addObserver(observer.capture());
         initMediator();
         observer.getValue().onStartedShowing(LayoutType.TAB_SWITCHER, false);
-        observer.getValue().onFinishedHiding(LayoutType.BROWSING);
+        observer.getValue().onFinishedShowing(LayoutType.BROWSING);
         verify(mMessageDispatcher).resume(EXPECTED_TOKEN);
     }