synchronize visibility of hosted_app_buttons with caption buttons

The hosted_app_buttons should be invisible when the caption buttons
(i.e. maximize/minimize/close buttons) are invisible.

Bug: 951068
Test: browser_tests
Change-Id: Ic944b6d90c3cda4397f38f34d5de86e2a26ca070
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1560314Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649320}

chrome/browser/ui/views/frame/browser_non_client_frame_view_ash.cc

@@ -546,8 +546,11 @@ void BrowserNonClientFrameViewAsh::OnTabletModeToggled(bool enabled) {
     OnImmersiveRevealEnded();
   }
 
-  caption_button_container_->SetVisible(ShouldShowCaptionButtons());
+  const bool should_show_caption_buttons = ShouldShowCaptionButtons();
+  caption_button_container_->SetVisible(should_show_caption_buttons);
   caption_button_container_->UpdateCaptionButtonState(true /*=animate*/);
+  if (hosted_app_button_container())
+    hosted_app_button_container()->SetVisible(should_show_caption_buttons);
 
   if (enabled) {
     // Enter immersive mode if the feature is enabled and the widget is not
@@ -756,7 +759,10 @@ bool BrowserNonClientFrameViewAsh::ShouldPaint() const {
 }
 
 void BrowserNonClientFrameViewAsh::OnOverviewOrSplitviewModeChanged() {
-  caption_button_container_->SetVisible(ShouldShowCaptionButtons());
+  const bool should_show_caption_buttons = ShouldShowCaptionButtons();
+  caption_button_container_->SetVisible(should_show_caption_buttons);
+  if (hosted_app_button_container())
+    hosted_app_button_container()->SetVisible(should_show_caption_buttons);
 }
 
 std::unique_ptr<ash::FrameHeader>

chrome/browser/ui/views/frame/browser_non_client_frame_view_ash_browsertest.cc

@@ -936,6 +936,17 @@ IN_PROC_BROWSER_TEST_P(HostedAppNonClientFrameViewAshTest, FocusableViews) {
   EXPECT_TRUE(browser_view_->contents_web_view()->HasFocus());
 }
 
+IN_PROC_BROWSER_TEST_P(HostedAppNonClientFrameViewAshTest,
+                       ButtonVisibilityInOverviewMode) {
+  SetUpHostedApp();
+  EXPECT_TRUE(hosted_app_button_container_->visible());
+
+  ToggleOverview();
+  EXPECT_FALSE(hosted_app_button_container_->visible());
+  ToggleOverview();
+  EXPECT_TRUE(hosted_app_button_container_->visible());
+}
+
 // Tests that a web app's theme color is set.
 IN_PROC_BROWSER_TEST_P(HostedAppNonClientFrameViewAshTest, ThemeColor) {
   SetUpHostedApp();