Step 1 in unifying the task manager's WebContents-based ResourceProviders.

Motivation.

The primary motivation here is to centralize the tracking of WebContents, so
that the upcoming logic that shows cross-process iframes in the task manager
does not have to be copied five times. A secondary motivations is to eliminate
uses of some (but not all) deprecated notification service notifications,
switching to WebContentsObserver instead.

Design.

A new class, WebContentsResourceProvider, will provides resources to the task
manager on behalf of a chrome service that owns WebContentses. The chrome
services will be parameterized via another new interface,
WebContentsInformation, which provides a list of WebContentses to track and
also acts as a RendererResource* factory.

The WebContentsInformation is responsible for notifying the
WebContentsResourceProvider of the existence of new WebContents* instances
only (not deletion/updates). This is because for the rest of the tracking,
WebContentsResourceProvider creates a WebContentsObserver. The
WebContentsInformation impls will derive from, as an implementation detail, an
abstract base class called NotificationObservingWebContentsInformation. This
base class takes care of listening for NOTIFICATION_WEB_CONTENTS_CONNECTED.

In this CL, serving as an example, only the Panel resource provider is
replaced: PanelResourceProvider just becomes a much smaller PanelInformation,
and the TaskManager instantiates a WebContentsResourceProvider, passing
instance of PanelInformation as its |info_| parameter.

Direction.

In subsequent CLs this new mechanism will subsume the commonly implemented
parts of Extension, Panel, TabContents, and Background resource providers.
This promises to be a net deletion of code, on account of how much duplicate
functionality existed between these classes.

BUG=348836
TEST=browser_tests

Review URL: https://codereview.chromium.org/196203003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258545 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 52 insertions, 0 deletions

diff --git a/chrome/browser/task_manager/web_contents_information.cc b/chrome/browser/task_manager/web_contents_information.cc
new file mode 100644
index 0000000..c82cd16
--- /dev/null
+++ b/chrome/browser/task_manager/web_contents_information.cc
@@ -0,0 +1,52 @@
+// 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 "chrome/browser/task_manager/web_contents_information.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+
+namespace task_manager {
+
+WebContentsInformation::WebContentsInformation() {}
+
+WebContentsInformation::~WebContentsInformation() {}
+
+NotificationObservingWebContentsInformation::
+    NotificationObservingWebContentsInformation() {}
+
+NotificationObservingWebContentsInformation::
+    ~NotificationObservingWebContentsInformation() {}
+
+void NotificationObservingWebContentsInformation::StartObservingCreation(
+    const NewWebContentsCallback& callback) {
+  observer_callback_ = callback;
+  registrar_.Add(this,
+                 content::NOTIFICATION_WEB_CONTENTS_CONNECTED,
+                 content::NotificationService::AllBrowserContextsAndSources());
+}
+
+void NotificationObservingWebContentsInformation::StopObservingCreation() {
+  registrar_.Remove(
+      this,
+      content::NOTIFICATION_WEB_CONTENTS_CONNECTED,
+      content::NotificationService::AllBrowserContextsAndSources());
+  observer_callback_.Reset();
+}
+
+void NotificationObservingWebContentsInformation::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  content::WebContents* web_contents =
+      content::Source<content::WebContents>(source).ptr();
+
+  switch (type) {
+    case content::NOTIFICATION_WEB_CONTENTS_CONNECTED:
+      if (CheckOwnership(web_contents))
+        observer_callback_.Run(web_contents);
+      break;
+  }
+}
+
+}  // namespace task_manager