Add support for transparent background API

chrome/renderer/resources/extensions/app_window_custom_bindings.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Custom binding for the app_window API.
 
 var appWindowNatives = requireNative('app_window_natives');
 var runtimeNatives = requireNative('runtime');
 var Binding = require('binding').Binding;
 var Event = require('event_bindings').Event;
@@ skipping 222 matching lines @@
     };
     AppWindow.prototype.isMinimized = function() {
       return appWindowData.minimized;
     };
     AppWindow.prototype.isMaximized = function() {
       return appWindowData.maximized;
     };
     AppWindow.prototype.isAlwaysOnTop = function() {
       return appWindowData.alwaysOnTop;
     };
+    AppWindow.prototype.alphaEnabled = function() {
+      return appWindowData.alphaEnabled;
+    };
 
     Object.defineProperty(AppWindow.prototype, 'id', {get: function() {
       return appWindowData.id;
     }});
 
     // These properties are for testing.
     Object.defineProperty(
         AppWindow.prototype, 'hasFrameColor', {get: function() {
       return appWindowData.hasFrameColor;
     }});
@@ skipping 29 matching lines @@
 
         minWidth: params.outerBounds.minWidth,
         minHeight: params.outerBounds.minHeight,
         maxWidth: params.outerBounds.maxWidth,
         maxHeight: params.outerBounds.maxHeight
       },
       fullscreen: params.fullscreen,
       minimized: params.minimized,
       maximized: params.maximized,
       alwaysOnTop: params.alwaysOnTop,
+      alphaEnabled: params.alphaEnabled,
       hasFrameColor: params.hasFrameColor,
       activeFrameColor: params.activeFrameColor,
       inactiveFrameColor: params.inactiveFrameColor
     };
     currentAppWindow = new AppWindow;
   });
 });
 
 function boundsEqual(bounds1, bounds2) {
   if (!bounds1 || !bounds2)
@@ skipping 29 matching lines @@
     dispatchEventIfExists(currentWindow, "onFullscreened");
   if (!oldData.minimized && update.minimized)
     dispatchEventIfExists(currentWindow, "onMinimized");
   if (!oldData.maximized && update.maximized)
     dispatchEventIfExists(currentWindow, "onMaximized");
 
   if ((oldData.fullscreen && !update.fullscreen) ||
       (oldData.minimized && !update.minimized) ||
       (oldData.maximized && !update.maximized))
     dispatchEventIfExists(currentWindow, "onRestored");
+
+  if (oldData.alphaEnabled != update.alphaEnabled)
+    dispatchEventIfExists(currentWindow, "onAlphaEnabledChanged");

[benwells, 2014/05/12 04:25:17]

With the curernt code, this will never happen, and isn't tested. Is that right?
will it be used soon? I'm hesitant to add code that isn't triggered or tested;
maybe this should come in a later CL.

[garykac, 2014/07/09 23:19:21]

Removed for later cl. This should be called when the platform switches from a
mode that supports transparency to one that doesn't (and vice-versa). I'm not
sure yet where the hooks are for that.

[jackhou1, 2014/07/10 03:06:55]

CL is here btw: https://codereview.chromium.org/375183002/

[garykac, 2014/07/25 22:50:31]

Acknowledged.

 };
 
 function onAppWindowClosed() {
   if (!currentAppWindow)
     return;
   dispatchEventIfExists(currentAppWindow, "onClosed");
 }
 
 function updateBounds(boundsType, bounds) {
   if (!currentWindowInternal)
@@ skipping 13 matching lines @@
     if (value === null)
       constraints[key] = 0;
   });
 
   currentWindowInternal.setSizeConstraints(boundsType, constraints);
 }
 
 exports.binding = appWindow.generate();
 exports.onAppWindowClosed = onAppWindowClosed;
 exports.updateAppWindowProperties = updateAppWindowProperties;