aura: No shadow for transparent window.

ash/wm/shadow_controller.cc

Index: ash/wm/shadow_controller.cc
diff --git a/ash/wm/shadow_controller.cc b/ash/wm/shadow_controller.cc
index 6f5a530ee7b9c73f5d78d70fb57ec02d1104dc6d..2d57d33cc61e9b8dfebdc1aef9308ca2b2f504ac 100644
--- a/ash/wm/shadow_controller.cc
+++ b/ash/wm/shadow_controller.cc
@@ -22,16 +22,17 @@ namespace internal {
 
 namespace {
 
-ShadowType GetShadowTypeFromWindowType(aura::Window* window) {
+ShadowType GetShadowTypeFromWindow(aura::Window* window) {
   switch (window->type()) {

[Ben Goodger (Google), 2012/01/25 23:02:36]

I think as a general rule transparent windows shouldn't have shadows... so
perhaps rather than putting the condition in each branch below you can just do a
test at the beginning and return early.

[xiyuan, 2012/01/25 23:33:14]

Done.

     case aura::client::WINDOW_TYPE_NORMAL:
     case aura::client::WINDOW_TYPE_PANEL:
       return CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kAuraTranslucentFrames) ?
+          switches::kAuraTranslucentFrames) || window->transparent() ?
               SHADOW_TYPE_NONE : SHADOW_TYPE_RECTANGULAR;
     case aura::client::WINDOW_TYPE_MENU:
     case aura::client::WINDOW_TYPE_TOOLTIP:
-      return SHADOW_TYPE_RECTANGULAR;
+      return window->transparent() ? SHADOW_TYPE_NONE :
+                                     SHADOW_TYPE_RECTANGULAR;
     default:
       break;
   }
@@ -54,7 +55,7 @@ ShadowController::~ShadowController() {
 
 void ShadowController::OnWindowInitialized(aura::Window* window) {
   window->AddObserver(this);
-  SetShadowType(window, GetShadowTypeFromWindowType(window));
+  SetShadowType(window, GetShadowTypeFromWindow(window));
   HandlePossibleShadowVisibilityChange(window);
 }