Add app.window.alphaEnabled() and onAlphaEnabledChanged.

chrome/common/extensions/api/app_window.idl

Index: chrome/common/extensions/api/app_window.idl
diff --git a/chrome/common/extensions/api/app_window.idl b/chrome/common/extensions/api/app_window.idl
index b08037bf327bddf1dfbb1ba6e508493e54cff19d..cf6a67e52ccffc75d332a06075c3138a28913ddd 100644
--- a/chrome/common/extensions/api/app_window.idl
+++ b/chrome/common/extensions/api/app_window.idl
@@ -351,6 +351,9 @@ namespace app.window {
     // <code>"alwaysOnTopWindows"</code> permission.
     static void setAlwaysOnTop(boolean alwaysOnTop);
 
+    // Whether alpha is enabled for this window.

[Wez, 2014/07/09 22:03:30]

nit: Suggest "Does the window have access to alpha transparency?" or "Can the
window use alpha transparency?"to fit the style of comments on similar getters.

[jackhou1, 2014/07/10 03:04:18]

Done.

+    [nodoc] static boolean alphaEnabled();
+
     // The JavaScript 'window' object for the created child.
     [instanceOf=Window] object contentWindow;
 
@@ -433,6 +436,9 @@ namespace app.window {
     // Fired when the window is restored from being minimized or maximized.
     [nocompile] static void onRestored();
 
+    // Fired when window.alphaEnabled changes.

[Wez, 2014/07/09 22:03:30]

nit: This is obvious from the name; suggest "Fired when the window's ability to
use alpha transparency changes."

[jackhou1, 2014/07/10 03:04:18]

Done.

+    [nocompile, nodoc] static void onAlphaEnabledChanged();
+
     // Event for testing. Lets tests wait until a window has been shown.
     [nocompile, nodoc] static void onWindowFirstShown();
   };