Add experimental code behind a flag for Content Size Policy

content/browser/loader/loader_io_thread_notifier.h

Index: content/browser/loader/loader_io_thread_notifier.h
diff --git a/content/browser/loader/loader_io_thread_notifier.h b/content/browser/loader/loader_io_thread_notifier.h
index 8528ecde6cbfa81723a9255c4d7c8cdfe79635bd..8c153b8c337bfa4646f9a9265b40bfe532d03da5 100644
--- a/content/browser/loader/loader_io_thread_notifier.h
+++ b/content/browser/loader/loader_io_thread_notifier.h
@@ -6,10 +6,14 @@
 #define CONTENT_BROWSER_LOADER_LOADER_IO_THREAD_NOTIFIER
 
 #include "base/macros.h"
+#include "content/browser/loader/global_routing_id.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 
+class FrameTreeNode;
+class NavigationHandle;
 class RenderFrameHost;
 class WebContents;
 
@@ -23,10 +27,40 @@ class LoaderIOThreadNotifier : public WebContentsObserver {
   explicit LoaderIOThreadNotifier(WebContents* web_contents);
   ~LoaderIOThreadNotifier() override;
 
-  // content::WebContentsObserver:
+  // WebContentsObserver:
+  void RenderFrameCreated(RenderFrameHost* render_frame_host) override;
   void RenderFrameDeleted(RenderFrameHost* render_frame_host) override;
 
+  static void UpdateGlobalDataAccounting(
+      std::unique_ptr<std::map<GlobalFrameRoutingId, int>> updates);
+
+  static NavigationThrottle* MaybeCreateThrottle(NavigationHandle* handle);
+  NavigationThrottle::ThrottleCheckResult WillProcessNavigationResponse(
+      NavigationHandle* handle);
+
  private:
+  struct FrameSize {
+    int content_left = 0;
+    int content_limit = 0;
+  };
+
+  // Returns the effective size limit of this FrameTreeNode by walking up the
+  // tree.
+  LoaderIOThreadNotifier::FrameSize* AddNewFrame(FrameTreeNode* node,
+                                                 int limit);
+  LoaderIOThreadNotifier::FrameSize* GetEffectiveLimit(FrameTreeNode* node);
+
+  static void NotifyFramesWentOverSizeLimits(
+      std::unique_ptr<std::set<GlobalFrameRoutingId>> frames);
+  static void NotifyFrameHasLimit(const GlobalFrameRoutingId& frame,
+                                  int limit);
+
+  void UpdateDataAccounting(
+      std::map<GlobalFrameRoutingId, int> updates);
+
+  // frame_tree_node_id -> FrameSize map.
+  std::map<int, FrameSize> frame_tree_node_sizes_;

[mmenke, 2016/08/05 17:16:27]

This really doesn't belong in something called "LoaderIOThreadNotifier".  It has
nothing to do with notifying the IOThread of anything.

We need to store stuff on the UI thread, though, and learn about new frames
there.  Maybe a new WebContentsObserver, instead, specifically for this
component?

Alternatively, could make a separate class, and have this one own it can call
into it.

[Charlie Harrison, 2016/08/08 14:04:39]

Fair point. I mainly stuffed this logic here because this was the class designed
to be glue between loader-related things on the UI/IO thread. I've added another
class: ContentSizeFrameCounter, that is another WebContentsObserver, and kept
this class as-is.

+
   DISALLOW_COPY_AND_ASSIGN(LoaderIOThreadNotifier);
 };