Apply new MD shadows to CrOS tray bubbles.

ui/wm/core/shadow_controller.cc

Index: ui/wm/core/shadow_controller.cc
diff --git a/ui/wm/core/shadow_controller.cc b/ui/wm/core/shadow_controller.cc
index 76a2ae2cc5ca6911b3a3973387250187f8e60974..123505c139cad5e0923a3f2cd0d56ba276a256c7 100644
--- a/ui/wm/core/shadow_controller.cc
+++ b/ui/wm/core/shadow_controller.cc
@@ -46,20 +46,22 @@ ShadowType GetShadowTypeFromWindow(aura::Window* window) {
   return SHADOW_TYPE_NONE;
 }
 
-bool ShouldUseSmallShadowForWindow(aura::Window* window) {
+Shadow::Style GetShadowStyleForWindow(aura::Window* window) {
   switch (window->type()) {
     case ui::wm::WINDOW_TYPE_MENU:
     case ui::wm::WINDOW_TYPE_TOOLTIP:
-      return true;
+      return Shadow::STYLE_SMALL;
+
+    // System tray bubbles render like active windows. TODO(estade): this
+    // mechanism will need to be revisited for applying WM shadows to other
+    // types of bubbles which don't want to render such large shadows.
+    case ui::wm::WINDOW_TYPE_POPUP:

[James Cook, 2016/12/09 19:40:13]

From the code this looks like it will apply large shadows to non-bubble windows
(like any Widget of type frameless, and drag widgets too:

https://cs.chromium.org/chromium/src/ui/views/widget/widget_aura_utils.cc?l=2...

That seems undesirable to me, even in the short term.

[Evan Stade, 2016/12/09 21:09:18]

I'll look into it. I had hoped that other popups weren't getting WM shadows.

[Evan Stade, 2016/12/09 21:20:32]

Do you have an example of a drag widget? When I drag a bookmark bar button or
something inside a webpage, I don't see a shadow of any kind. When I drag a
window around, I assume that's still using the same window, which is active.

+      return Shadow::STYLE_ACTIVE;
+
     default:
-      break;
+      return IsActiveWindow(window) ? Shadow::STYLE_ACTIVE
+                                    : Shadow::STYLE_INACTIVE;
   }
-  return false;
-}
-
-Shadow::Style GetShadowStyleForWindow(aura::Window* window) {
-  return ShouldUseSmallShadowForWindow(window) ? Shadow::STYLE_SMALL :
-      (IsActiveWindow(window) ? Shadow::STYLE_ACTIVE : Shadow::STYLE_INACTIVE);
 }
 
 // Returns the shadow style to be applied to |losing_active| when it is losing
@@ -194,12 +196,13 @@ void ShadowController::Impl::OnWindowActivated(ActivationReason reason,
                                                aura::Window* lost_active) {
   if (gained_active) {
     Shadow* shadow = GetShadowForWindow(gained_active);
-    if (shadow && !ShouldUseSmallShadowForWindow(gained_active))
-      shadow->SetStyle(Shadow::STYLE_ACTIVE);
+    if (shadow)
+      shadow->SetStyle(GetShadowStyleForWindow(gained_active));
   }
   if (lost_active) {
     Shadow* shadow = GetShadowForWindow(lost_active);
-    if (shadow && !ShouldUseSmallShadowForWindow(lost_active)) {
+    if (shadow &&
+        GetShadowStyleForWindow(lost_active) == Shadow::STYLE_INACTIVE) {

[James Cook, 2016/12/09 19:40:13]

Shouldn't you be checking if the window that lost activation was previously
active? Or always updating the style?

[Evan Stade, 2016/12/09 21:09:18]

I don't think this change affects the behavior at all, does it? 

[James Cook, 2016/12/10 00:19:16]

What if |lost_active| had shadow style Shadow::STYLE_ACTIVE? You should reset
the shadow style to inactive, right?

       shadow->SetStyle(GetShadowStyleForWindowLosingActive(lost_active,
                                                            gained_active));
     }