Transparent apps support

chrome/browser/ui/views/extensions/native_app_window_views.cc

 // 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.
 
 #include "chrome/browser/ui/views/extensions/native_app_window_views.h"
 
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/favicon/favicon_tab_helper.h"
 #include "chrome/browser/ui/views/extensions/extension_keybinding_registry_views.h"
 #include "chrome/browser/ui/views/extensions/shell_window_frame_view.h"
@@ skipping 28 matching lines @@
 const int kResizeInsideBoundsSize = 5;
 }
 
 NativeAppWindowViews::NativeAppWindowViews(
     ShellWindow* shell_window,
     const ShellWindow::CreateParams& create_params)
     : shell_window_(shell_window),
       web_view_(NULL),
       window_(NULL),
       is_fullscreen_(false),
-      frameless_(create_params.frame == ShellWindow::FRAME_NONE) {
+      frameless_(create_params.frame == ShellWindow::FRAME_NONE),
+      transparent_background_(create_params.transparent_background) {
+  Observe(shell_window_->web_contents());
   minimum_size_ = create_params.minimum_size;
   maximum_size_ = create_params.maximum_size;
 
   window_ = new views::Widget;
   if (create_params.window_type == ShellWindow::WINDOW_TYPE_PANEL)
     InitializePanelWindow(create_params);
   else
     InitializeDefaultWindow(create_params);
 
   extension_keybinding_registry_.reset(
@@ skipping 324 matching lines @@
 void NativeAppWindowViews::OnWidgetVisibilityChanged(views::Widget* widget,
                                                      bool visible) {
   shell_window_->OnNativeWindowChanged();
 }
 
 void NativeAppWindowViews::OnWidgetActivationChanged(views::Widget* widget,
                                                      bool active) {
   shell_window_->OnNativeWindowChanged();
 }
 
+// WebContentsObserver implementation.
+
+void NativeAppWindowViews::RenderViewCreated(
+    content::RenderViewHost* render_view_host) {
+  if (transparent_background_) {
+    // Use a background with transparency to trigger transparency in Webkit.
+    SkBitmap background;
+    background.setConfig(SkBitmap::kARGB_8888_Config, 1, 1);
+    background.allocPixels();
+    background.eraseARGB(0x00, 0x00, 0x00, 0x00);
+
+    content::RenderWidgetHostView* view = render_view_host->GetView();
+    DCHECK(view);
+    view->SetBackground(background);
+  }
+}
+
 // views::View implementation.
 
 void NativeAppWindowViews::Layout() {
   DCHECK(web_view_);
   web_view_->SetBounds(0, 0, width(), height());
   OnViewWasResized();
 }
 
 void NativeAppWindowViews::ViewHierarchyChanged(
     bool is_add, views::View *parent, views::View *child) {
@@ skipping 72 matching lines @@
 }
 
 //------------------------------------------------------------------------------
 // NativeAppWindow::Create
 
 // static
 NativeAppWindow* NativeAppWindow::Create(
     ShellWindow* shell_window, const ShellWindow::CreateParams& params) {
   return new NativeAppWindowViews(shell_window, params);
 }