Add BubbleManager to manage bubbles and ChromeBubbleManager for events.

chrome/browser/ui/chrome_bubble_manager_factory.h

+// Copyright 2015 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.
+
+#ifndef CHROME_BROWSER_UI_CHROME_BUBBLE_MANAGER_FACTORY_H_
+#define CHROME_BROWSER_UI_CHROME_BUBBLE_MANAGER_FACTORY_H_
+
+#include "base/memory/singleton.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+class ChromeBubbleManager;
+
+class ChromeBubbleManagerFactory : public BrowserContextKeyedServiceFactory {

[msw, 2015/08/13 03:37:21]

I'm somewhat confused as to why we need a factory and a
ChromeBubbleManagerInstance for each browser context if each bubble itself has
some associated context. In the long term, do we plan to manage all bubbles from
a single manager? (maybe the manager would need some notion of context hierarchy
between tabs and browsers, etc. but that doesn't seem unreasonably hard)

[groby-ooo-7-16, 2015/08/13 18:44:38]

The BrowserContext is the wider context across which bubbles are managed. Each
browser needs to do that separately, because the bubbles don't interact across
browsers. 

However, bubbles can interact across WebContents - the BubbleManager coordinates
that. The individual context for a bubble is whatever content it is associated
with - either the WebContents, or the BrowserWindow that the bubble is
associated with. 

So we'll never have a single manager for all BrowserContexts, because they never
interact. 

[msw, 2015/08/13 19:18:58]

I'm not sure I understand what sort of interaction bubbles should actually have
across web-contents. Having a manager for each browser window might be
reasonable, but it might also be unnecessary.

+ public:
+  static ChromeBubbleManager* GetForBrowserContext(
+      content::BrowserContext* context);
+
+  static ChromeBubbleManagerFactory* GetInstance();
+
+ private:
+  friend struct DefaultSingletonTraits<ChromeBubbleManagerFactory>;
+
+  ChromeBubbleManagerFactory();
+  ~ChromeBubbleManagerFactory() override;
+
+  // BrowserContextKeyedServiceFactory:
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* context) const override;
+};
+
+#endif  // CHROME_BROWSER_UI_CHROME_BUBBLE_MANAGER_FACTORY_H_