Don't revalidate all resources for FrameLoadTypeSame

Source/core/loader/FrameFetchContext.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 144 matching lines @@
         return ReturnCacheDataElseLoad;
     return UseProtocolCachePolicy;
 }
 
 ResourceRequestCachePolicy FrameFetchContext::resourceRequestCachePolicy(const ResourceRequest& request, Resource::Type type) const
 {
     if (type == Resource::MainResource) {
         FrameLoadType frameLoadType = frame()->loader().loadType();
         if (request.httpMethod() == "POST" && frameLoadType == FrameLoadTypeBackForward)
             return ReturnCacheDataDontLoad;
-        if (!frame()->host()->overrideEncoding().isEmpty() || frameLoadType == FrameLoadTypeBackForward)
+        if (!frame()->host()->overrideEncoding().isEmpty())
             return ReturnCacheDataElseLoad;
-        if (frameLoadType == FrameLoadTypeReloadFromOrigin)
-            return ReloadBypassingCache;
-        if (frameLoadType == FrameLoadTypeReload || frameLoadType == FrameLoadTypeSame || request.isConditional() || request.httpMethod() == "POST")
+        if (frameLoadType == FrameLoadTypeSame || request.isConditional() || request.httpMethod() == "POST")
             return ReloadIgnoringCacheData;
-        Frame* parent = frame()->tree().parent();
-        if (parent && parent->isLocalFrame())
-            return toLocalFrame(parent)->document()->fetcher()->context().resourceRequestCachePolicy(request, type);
+
+        for (Frame* f = frame(); f; f = f->tree().parent()) {

[Nate Chapin, 2015/07/15 18:24:03]

This function is no longer recursive. Everything above this line only applies to
the current frame (or the request). If none of those early returns trigger, we
walk up the frame tree (starting with the current frame) looking for an ancestor
that has a load type that modifies cache policy.

[dcheng, 2015/07/16 06:55:47]

Incidentally, is this OK to potentially skip ancestors in the walk up the tree?

[Nate Chapin, 2015/07/16 18:05:41]

In general, either (1) an iframe load is a navigation unto itself, and its
parent will be FrameLoadTypeStandard (i.e., the "i'm not loading right now"
state), or (2) The FrameLoadType will be the same all the way down. So I think
this is OK.

+            if (!f->isLocalFrame())
+                continue;
+            frameLoadType = toLocalFrame(f)->loader().loadType();
+            if (frameLoadType == FrameLoadTypeBackForward)
+                return ReturnCacheDataElseLoad;
+            if (frameLoadType == FrameLoadTypeReloadFromOrigin)
+                return ReloadBypassingCache;
+            if (frameLoadType == FrameLoadTypeReload)
+                return ReloadIgnoringCacheData;
+        }
         return UseProtocolCachePolicy;
     }
 
     if (request.isConditional())
         return ReloadIgnoringCacheData;
 
     if (m_documentLoader && m_document && !m_document->loadEventFinished()) {
         // For POST requests, we mutate the main resource's cache policy to avoid form resubmission.
         // This policy should not be inherited by subresources.
         ResourceRequestCachePolicy mainResourceCachePolicy = m_documentLoader->request().cachePolicy();
@@ skipping 478 matching lines @@
 }
 
 DEFINE_TRACE(FrameFetchContext)
 {
     visitor->trace(m_document);
     visitor->trace(m_documentLoader);
     FetchContext::trace(visitor);
 }
 
 } // namespace blink