Adding overview / layer framework to Activities so that unloaded / sleeping activities can be shown…

athena/content/content_proxy.cc

Index: athena/content/content_proxy.cc
diff --git a/athena/content/content_proxy.cc b/athena/content/content_proxy.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8e51696a168172a0e05e05aeb43dd42f39f67210
--- /dev/null
+++ b/athena/content/content_proxy.cc
@@ -0,0 +1,128 @@
+// Copyright 2014 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 "athena/content/content_proxy.h"
+
+#include "athena/activity/public/activity.h"
+#include "athena/activity/public/activity_view_model.h"
+#include "content/public/browser/web_contents.h"
+#include "ui/aura/window.h"
+#include "ui/views/background.h"
+#include "ui/views/controls/webview/webview.h"
+#include "ui/views/widget/widget.h"
+
+namespace athena {
+
+ContentProxy::ContentProxy(views::WebView* web_view, Activity* activity)
+    : web_view_(web_view),
+      window_(activity->GetWindow()),
+      background_color_(
+          activity->GetActivityViewModel()->GetRepresentativeColor()),
+      content_loaded_(true) {
+  CreateProxyContent();
+  HideOriginalContent();
+}
+
+ContentProxy::~ContentProxy() {
+  // If we still have a connection to the original Activity, we make it visible
+  // again.
+  ShowOriginalContent();
+  proxy_content_.reset();
+}
+
+void ContentProxy::ContentWillUnload() {
+  content_loaded_ = false;
+}
+
+gfx::ImageSkia ContentProxy::GetContentImage() {
+  // For the time being we keep this here and return an empty image.
+  return image_;
+}
+
+void ContentProxy::EvictContent() {
+  HideProxyContent();
+  CreateSolidProxyContent();
+  ShowProxyContent();
+}
+
+void ContentProxy::Reparent(aura::Window* new_parent_window) {
+  if (new_parent_window == window_)
+    return;
+
+  // Since we are breaking now the connection to the old content, we make the
+  // content visible again before we continue.
+  // Note: Since the owning window is invisible, it does not matter that we
+  // make the web content visible if the window gets destroyed shortly after.
+  ShowOriginalContent();
+
+  // Transfer the |proxy_content_| to the passed window.
+  window_ = new_parent_window;
+  web_view_ = NULL;
+
+  // Move the view to the new window and show it there.
+  HideOriginalContent();
+}
+
+void ContentProxy::ShowOriginalContent() {
+  // Hide our content.
+  HideProxyContent();
+
+  if (web_view_) {
+    // Show the original |web_view_| again.
+    web_view_->SetFastResize(false);
+    // If the content is loaded, we ask it to relayout itself since the
+    // dimensions might have changed. If not, we will reload new content and no
+    // layout is required for the old content.
+    if (content_loaded_)
+      web_view_->Layout();
+    web_view_->GetWebContents()->GetNativeView()->Show();
+    web_view_->SetVisible(true);
+  }
+}
+
+void ContentProxy::HideOriginalContent() {
+  if (web_view_) {
+    // Hide the |web_view_|.
+    // TODO(skuhne): We might consider removing the view from the window while
+    // it's hidden - it should work the same way as show/hide and does not have
+    // any window re-ordering effect.
+    web_view_->GetWebContents()->GetNativeView()->Hide();
+    web_view_->SetVisible(false);
+    // Don't allow the content to get resized with window size changes.
+    web_view_->SetFastResize(true);
+  }
+
+  // Show our replacement content.
+  ShowProxyContent();
+}
+
+void ContentProxy::CreateProxyContent() {
+  // For the time being we create only a solid color here.
+  // TODO(skuhne): Replace with copying the drawn content into |proxy_content_|
+  // instead.
+  CreateSolidProxyContent();
+}
+
+void ContentProxy::CreateSolidProxyContent() {
+  proxy_content_.reset(new views::View());
+  proxy_content_->set_background(
+      views::Background::CreateSolidBackground(background_color_));
+  proxy_content_->SetFillsBoundsOpaquely(true);

[pkotwicz, 2014/09/10 14:30:21]

Are there any cases where |proxy_content_| is painted to a ui::Layer? (i.e.
View::SetPaintToLayer() is called?)
If there are not any, View::SetFillsBoundsOpaquely() is a no-op

[Mr4D (OOO till 08-26), 2014/09/10 15:55:45]

Removed.

+}
+
+void ContentProxy::ShowProxyContent() {
+  views::Widget* widget = views::Widget::GetWidgetForNativeWindow(window_);
+  views::View* client_view = widget->client_view();
+  // Place the view in front of all others.
+  client_view->AddChildViewAt(proxy_content_.get(), 0);
+  proxy_content_->SetSize(client_view->bounds().size());
+}
+
+void ContentProxy::HideProxyContent() {
+  views::Widget* widget = views::Widget::GetWidgetForNativeWindow(window_);
+  views::View* client_view = widget->client_view();
+  client_view->RemoveChildView(proxy_content_.get());

[Jun Mukai, 2014/09/10 00:38:53]

views::View instance is owned by its parent.  Therefore, after this line,
|proxy_content_| will hold the pointer to the removed view.

You may want to use pointer instead of scoped_ptr.

[Mr4D (OOO till 08-26), 2014/09/10 15:55:45]

Right - but the view does not get deleted by this command. The idea being that
the Show / hide can be called multiple times and the view could even be passed
to someone else if we want to paint it in another window. To ensure its proper
deletion I have put it into a scoped_ptr.

Makes sense?

[Jun Mukai, 2014/09/10 21:04:57]

Ah, I see, I was wrong (I believed RemoveChildView implicitly removes the view).

+}
+
+}  // namespace athena