Reland: "Mash browser frame: fix rendering in single tab mode"

This relands da08ce6d

Single tab mode makes the frame the same color as a tab.

There's no change from the original patchset, which was reverted
to make it easier to revert the actual culprit 5f93deb6

TBR=msw@chromium.org

Bug: 854704
Change-Id: I1fb8eeb5ae736501f79676668b146d1c8ac32193
Reviewed-on: https://chromium-review.googlesource.com/1125512Reviewed-by: Evan Stade <estade@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572448}

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

@@ -70,6 +70,7 @@ int BrowserNonClientFrameView::GetAvatarIconPadding() {
 
 void BrowserNonClientFrameView::OnBrowserViewInitViewsComplete() {
   MaybeObserveTabstrip();
+  OnSingleTabModeChanged();
   UpdateMinimumSize();
 }
 

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

@@ -252,6 +252,15 @@ BrowserNonClientFrameViewAsh::CreateInterfacePtrForTesting() {
 ///////////////////////////////////////////////////////////////////////////////
 // BrowserNonClientFrameView:
 
+void BrowserNonClientFrameViewAsh::OnSingleTabModeChanged() {
+  if (!IsMash()) {
+    BrowserNonClientFrameView::OnSingleTabModeChanged();
+    return;
+  }
+
+  UpdateFrameColors();
+}
+
 gfx::Rect BrowserNonClientFrameViewAsh::GetBoundsForTabStrip(
     views::View* tabstrip) const {
   if (!tabstrip)
@@ -662,28 +671,7 @@ void BrowserNonClientFrameViewAsh::OnThemeChanged() {
   inactive_frame_overlay_image_registration_ = update_window_image(
       ash::kFrameImageOverlayInactiveKey, GetFrameOverlayImage(false));
 
-  base::Optional<SkColor> active_color, inactive_color;
-  if (!UsePackagedAppHeaderStyle(browser_view()->browser())) {
-    active_color = GetFrameColor(true);
-    inactive_color = GetFrameColor(false);
-  } else if (extensions::HostedAppBrowserController::
-                 IsForExperimentalHostedAppBrowser(browser_view()->browser())) {
-    base::Optional<SkColor> theme_color =
-        browser_view()->browser()->hosted_app_controller()->GetThemeColor();
-    window->SetProperty(ash::kFrameIsThemedByHostedAppKey, !!theme_color);
-
-    if (theme_color)
-      active_color = SkColorSetA(*theme_color, SK_AlphaOPAQUE);
-  } else {
-    active_color = kMdWebUiFrameColor;
-  }
-
-  if (active_color) {
-    window->SetProperty(ash::kFrameActiveColorKey, *active_color);
-    window->SetProperty(ash::kFrameInactiveColorKey,
-                        inactive_color.value_or(*active_color));
-  }
-
+  UpdateFrameColors();
   BrowserNonClientFrameView::OnThemeChanged();
 }
 
@@ -1075,3 +1063,33 @@ void BrowserNonClientFrameViewAsh::StartHostedAppAnimation() {
   hosted_app_button_container_->StartTitlebarAnimation(
       frame_header_origin_text_->AnimationDuration());
 }
+
+void BrowserNonClientFrameViewAsh::UpdateFrameColors() {
+  DCHECK(IsMash());
+
+  aura::Window* window = frame()->GetNativeWindow();
+  base::Optional<SkColor> active_color, inactive_color;
+  if (!UsePackagedAppHeaderStyle(browser_view()->browser())) {
+    active_color = GetFrameColor(true);
+    inactive_color = GetFrameColor(false);
+  } else if (extensions::HostedAppBrowserController::
+                 IsForExperimentalHostedAppBrowser(browser_view()->browser())) {
+    base::Optional<SkColor> theme_color =
+        browser_view()->browser()->hosted_app_controller()->GetThemeColor();
+    window->SetProperty(ash::kFrameIsThemedByHostedAppKey, !!theme_color);
+
+    if (theme_color)
+      active_color = SkColorSetA(*theme_color, SK_AlphaOPAQUE);
+  } else {
+    active_color = kMdWebUiFrameColor;
+  }
+
+  if (active_color) {
+    window->SetProperty(ash::kFrameActiveColorKey, *active_color);
+    window->SetProperty(ash::kFrameInactiveColorKey,
+                        inactive_color.value_or(*active_color));
+  } else {
+    window->ClearProperty(ash::kFrameActiveColorKey);
+    window->ClearProperty(ash::kFrameInactiveColorKey);
+  }
+}

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

@@ -60,6 +60,7 @@ class BrowserNonClientFrameViewAsh
   ash::mojom::SplitViewObserverPtr CreateInterfacePtrForTesting();
 
   // BrowserNonClientFrameView:
+  void OnSingleTabModeChanged() override;
   gfx::Rect GetBoundsForTabStrip(views::View* tabstrip) const override;
   int GetTopInset(bool restored) const override;
   int GetThemeBackgroundXInset() const override;
@@ -196,6 +197,9 @@ class BrowserNonClientFrameViewAsh
   // app UI elements exist.
   void StartHostedAppAnimation();
 
+  // To be called after the frame's colors may have changed.
+  void UpdateFrameColors();
+
   // View which contains the window controls.
   ash::FrameCaptionButtonContainerView* caption_button_container_ = nullptr;
 

chrome/browser/ui/views/tabs/tab_strip.cc

@@ -494,7 +494,7 @@ void TabStrip::AddTabAt(int model_index, TabRendererData data, bool is_active) {
 
   SwapLayoutIfNecessary();
 
-  if (was_single_tab_mode)
+  if (was_single_tab_mode != SingleTabMode())
     SingleTabModeChanged();
 
   for (TabStripObserver& observer : observers_)