Additions to Activities to allow resource management

athena/content/app_activity.cc

 // 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/app_activity.h"
 
 #include "apps/shell/browser/shell_app_window.h"
 #include "athena/activity/public/activity_manager.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/views/controls/webview/webview.h"
 
 namespace athena {
 
 // TODO(mukai): specifies the same accelerators of WebActivity.
 AppActivity::AppActivity(apps::ShellAppWindow* app_window)
-    : app_window_(app_window), web_view_(NULL) {
+    : app_window_(app_window),
+      web_view_(NULL),
+      current_state_(ACTIVITY_UNLOADED) {
   DCHECK(app_window_);
 }
 
 AppActivity::~AppActivity() {
+  if (GetCurrentState() != ACTIVITY_UNLOADED)
+    SetCurrentState(ACTIVITY_UNLOADED);
 }
 
 ActivityViewModel* AppActivity::GetActivityViewModel() {
   return this;
 }
 
+void AppActivity::SetCurrentState(Activity::ActivityState state) {
+  switch (state) {
+    case ACTIVITY_VISIBLE:
+      // Fall through (for the moment).
+    case ACTIVITY_INVISIBLE:
+      // By clearing the overview mode image we allow the content to be shown.
+      overview_mode_image_ = gfx::ImageSkia();
+      // TODO(skuhne): Find out how to reload an app from the extension system.
+      break;
+    case ACTIVITY_BACKGROUND_LOW_PRIORITY:
+      DCHECK(ACTIVITY_VISIBLE == current_state_ ||
+             ACTIVITY_INVISIBLE == current_state_);
+      // TODO(skuhne): Do this.
+      break;
+    case ACTIVITY_PERSISTENT:
+      DCHECK_EQ(ACTIVITY_BACKGROUND_LOW_PRIORITY, current_state_);
+      // TODO(skuhne): Do this.
+      break;
+    case ACTIVITY_UNLOADED:
+      DCHECK_NE(ACTIVITY_UNLOADED, current_state_);
+      // TODO(skuhne): Find out how to evict an app from the extension system.
+      //      web_view_->EvictContent();
+      break;
+  }
+  // Remember the last requested state.
+  current_state_ = state;
+}
+
+Activity::ActivityState AppActivity::GetCurrentState() {
+  // TODO(skuhne): Check here also eviction status.
+  if (!web_view_) {
+    DCHECK_EQ(ACTIVITY_UNLOADED, current_state_);
+    return ACTIVITY_UNLOADED;
+  }
+  // TODO(skuhne): This should be controlled by an observer and should not
+  // reside here.
+  if (IsVisible() && current_state_ != ACTIVITY_VISIBLE)
+    SetCurrentState(ACTIVITY_VISIBLE);
+  // Note: If the activity is not visible it does not necessarily mean that it
+  // does not have GPU compositor resources (yet).
+  return current_state_;
+}
+
+bool AppActivity::IsVisible() {
+  return web_view_ && web_view_->IsDrawn();
+}
+
+Activity::ActivityMediaState AppActivity::GetMediaState() {
+  // TODO(skuhne): The function GetTabMediaStateForContents(WebContents),
+  // and the AudioStreamMonitor needs to be moved from Chrome into contents to
+  // make it more modular and so that we can use it from here.
+  return Activity::ACTIVITY_MEDIA_STATE_NONE;
+}
+
 void AppActivity::Init() {
 }
 
 SkColor AppActivity::GetRepresentativeColor() const {
   // TODO(sad): Compute the color from the favicon.
   return SK_ColorGRAY;
 }
 
 base::string16 AppActivity::GetTitle() const {
   return web_view_->GetWebContents()->GetTitle();
 }
 
 bool AppActivity::UsesFrame() const {
   return false;
 }
 
 views::View* AppActivity::GetContentsView() {
   if (!web_view_) {
     // TODO(oshima): use apps::NativeAppWindowViews
     content::WebContents* web_contents =
         app_window_->GetAssociatedWebContents();
     web_view_ = new views::WebView(web_contents->GetBrowserContext());
     web_view_->SetWebContents(web_contents);
+    SetCurrentState(ACTIVITY_INVISIBLE);
     Observe(web_contents);
+    overview_mode_image_ = gfx::ImageSkia();
   }
   return web_view_;
 }
 
+void AppActivity::CreateOverviewModeImage() {
+  // TODO(skuhne): Implement this!
+}
+
+gfx::ImageSkia AppActivity::GetOverviewModeImage() {
+  return overview_mode_image_;
+}
+
 void AppActivity::TitleWasSet(content::NavigationEntry* entry,
                               bool explicit_set) {
   ActivityManager::Get()->UpdateActivity(this);
 }
 
 void AppActivity::DidUpdateFaviconURL(
     const std::vector<content::FaviconURL>& candidates) {
   ActivityManager::Get()->UpdateActivity(this);
 }
 
 }  // namespace athena