PlzNavigate: Make ServiceWorker work with PlzNavigate.

content/browser/frame_host/navigator_delegate.h

Index: content/browser/frame_host/navigator_delegate.h
diff --git a/content/browser/frame_host/navigator_delegate.h b/content/browser/frame_host/navigator_delegate.h
index 1494cc339f2ed24e5dcbc75f86475349a36489c1..070e8c76fe7b57e813f84ce286855939f1ffa249 100644
--- a/content/browser/frame_host/navigator_delegate.h
+++ b/content/browser/frame_host/navigator_delegate.h
@@ -17,6 +17,7 @@ struct FrameHostMsg_DidFailProvisionalLoadWithError_Params;
 
 namespace content {
 
+class BrowserContext;
 class FrameTreeNode;
 class NavigationHandle;
 class RenderFrameHostImpl;
@@ -130,6 +131,9 @@ class CONTENT_EXPORT NavigatorDelegate {
 
   // The load progress was changed.
   virtual void DidChangeLoadProgress() {}
+
+  // Helper method to access the BrowserContext.
+  virtual BrowserContext* GetBrowserContext() const;

[michaeln, 2015/10/01 23:11:12]

The NavigationController interface has a GetBrowserContext() method and the
Navigator has a navigation_controller_ data member. We should probably use that
to 'navigate' up the the browser context object.

Just curious. I see FrameTreeNodes have a reference to a Navigator. What is the
scope of a single Navigator(Impl) instance? How many nodes does a NavigatorImpl
servce concurrently and over its lifetime? From the looks of the
NavigationMetricsData, it looks like it could be a 1 to 1 relationship?

[clamy, 2015/10/02 10:34:44]

There is one NavigatorImpl per WebContents, and its lifetime is the lifetime of
the WebContents (same for the NavigationController). It services all the FTN of
the FrameTree. In this case, getting the BrowserContext through the
NavigationController is the right thing to do. In order to get to the
NavigationController, we should just keep a pointer to the FTN in the
NavigationHandle (a raw pointer is safe). In fact, it can replace the delegate
(since we can also get the Navigator and it's delegate from the FTN).

[Fabrice (no longer in Chrome), 2015/10/02 16:37:34]

Changed the argument to use a FrameTreeNode so this is removed. Thanks!

[michaeln, 2015/10/07 01:16:44]

Thnx for the explanation, the NavigationMetricsData threw me because it
obviously only applies to a single navigation. I see now that data only applies
to a navigation of the topmost frame.

 };
 
 }  // namspace content