Move WebUI ownership from the RenderFrameHostManager to the RenderFrameHost.

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index 84c579d8a494dc03e44a932f6250579806aacbf8..f7138cc489dbc0e4c883587ad61423eac84309b4 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -16,6 +16,7 @@
 #include "base/time/time.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/site_instance_impl.h"
+#include "content/browser/webui/web_ui_impl.h"
 #include "content/common/accessibility_mode_enums.h"
 #include "content/common/ax_content_node_data.h"
 #include "content/common/content_export.h"
@@ -213,6 +214,14 @@ class CONTENT_EXPORT RenderFrameHostImpl
   RenderFrameHostDelegate* delegate() { return delegate_; }
   FrameTreeNode* frame_tree_node() { return frame_tree_node_; }
 
+  // Returns the associated active WebUI or null if none applies.
+  WebUIImpl* web_ui() const { return web_ui_.get(); }
+
+  // Returns the pending WebUI, or null of none applies.
+  WebUIImpl* pending_web_ui() const {
+    return should_reuse_web_ui_ ? web_ui_.get() : pending_web_ui_.get();
+  }
+
   // Returns this RenderFrameHost's loading state. This method is only used by
   // FrameTreeNode. The proper way to check whether a frame is loading is to
   // call FrameTreeNode::IsLoading.
@@ -468,6 +477,35 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // addition, its associated RenderWidgetHost has to be focused.
   bool IsFocused();
 
+  // Initializes the first WebUI for a recently created RenderFrameHost, if one

[nasko, 2015/10/14 23:54:14]

Does the "recently created" bit matter?

[carlosk, 2015/10/15 16:34:07]

Removed it. It was not really true and the text that follows is clear enough:
"No WebUI must have been set before and it must be called only once"

+  // is required by |dest_url|. No WebUI must have been set before and it must
+  // be called only once. If this is a history navigation to an existing
+  // NavigationEntry, providing its |entry_bindings| will allow verifying that
+  // bindings are not being set differently this time around.
+  void InitializeWebUI(const GURL& dest_url, int entry_bindings);
+
+  // Updates the pending WebUI data of this RenderFrameHost based on the
+  // provided |dest_url|. If it doesn't require a WebUI, the pending one is
+  // cleared. If a new WebUI is required and its type matches the existing
+  // pending one it will be reused. If the type matches the active one then the
+  // pending is cleared and the current one is set to be reused. Otherwise a new
+  // pending WebUI instance is set.

[nasko, 2015/10/14 23:54:14]

As before, this comment seems to describe the implementation. Can you abstract
it such that it is less verbose?

[carlosk, 2015/10/15 16:34:07]

Simplified the comment.

[nasko, 2015/10/15 17:40:09]

This now is an awesome comment! Thank you!

+  // The WebUI chosen here will be made active upon the next call to
+  // CommitPendingWebUI.
+  // If this is a history navigation its bindings from the NavigationEntry
+  // should be provided through |entry_bindings|. It will allow verifying that
+  // bindings are not being set differently this time around. Otherwise
+  // |entry_bindings| should be set to NavigationEntryImpl::kInvalidBindings.
+  void UpdatePendingWebUI(const GURL& dest_url, int entry_bindings);
+
+  // Updates the active WebUI with the pending one set by the last call to
+  // UpdatePendingWebUI and then clears any pending data. If UpdatePendingWebUI
+  // was not called the active WebUI will simply be cleared.
+  void CommitPendingWebUI();
+
+  // Destroys the pending WebUI and cleans up any related data.
+  void DiscardPendingWebUI();
+
   // Returns the Mojo ImageDownloader service.
   const image_downloader::ImageDownloaderPtr& GetMojoImageDownloader();
 
@@ -622,6 +660,15 @@ class CONTENT_EXPORT RenderFrameHostImpl
       const content::StartNavigationParams& start_params,
       const content::RequestNavigationParams& request_params);
 
+  // Creates a WebUI object for the given URL if one applies and sets
+  // |web_ui_type| to its type, also ensuring that its bindings match
+  // |entry_bindings| (if provided and different than
+  // NavigationEntryImpl::kInvalidBindings). If no WebUI applies, returns

[nasko, 2015/10/14 23:54:14]

Again, no need to include the text in (). This is implementation detail.

[carlosk, 2015/10/15 16:34:07]

Done.

+  // null and resets web_ui_type to WebUI::kNoWebUI.
+  scoped_ptr<WebUIImpl> CreateWebUI(const GURL& dest_url,
+                                    int entry_bindings,
+                                    WebUI::TypeID* web_ui_type);
+
   // For now, RenderFrameHosts indirectly keep RenderViewHosts alive via a
   // refcount that calls Shutdown when it reaches zero.  This allows each
   // RenderFrameHostManager to just care about RenderFrameHosts, while ensuring
@@ -790,6 +837,21 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // NavigationHandle for it is owned by the NavigationRequest.
   scoped_ptr<NavigationHandleImpl> navigation_handle_;
 
+  // The associated WebUIImpl and its type. They will be set if the current page

[nasko, 2015/10/14 23:54:14]

This is RenderFrameHost, it cannot have a page : ). Let's use "the current
document is from WebUI source."

[carlosk, 2015/10/15 16:34:07]

Done.

+  // is a WebUI page. Otherwise they will be null and WebUI::kNoWebUI,
+  // respectively.
+  scoped_ptr<WebUIImpl> web_ui_;
+  WebUI::TypeID web_ui_type_;
+
+  // Stores a pending WebUIImpl and its type. These will only be set during a
+  // same-site navigation to a WebUI page (reusing this RenderFrameHost).
+  scoped_ptr<WebUIImpl> pending_web_ui_;
+  WebUI::TypeID pending_web_ui_type_;
+
+  // If true at commit time the current WebUI will simply be reused (no pending
+  // one will exist to be committed).
+  bool should_reuse_web_ui_;
+
   // NOTE: This must be the last member.
   base::WeakPtrFactory<RenderFrameHostImpl> weak_ptr_factory_;