Don't revalidate all resources for FrameLoadTypeSame

Source/core/loader/FrameFetchContext.cpp

Index: Source/core/loader/FrameFetchContext.cpp
diff --git a/Source/core/loader/FrameFetchContext.cpp b/Source/core/loader/FrameFetchContext.cpp
index 208b1c540e5eb3ec74590b6b9117d6e78e68bbb0..aface1a5911c278671f41a20ae9e35fa7e787d12 100644
--- a/Source/core/loader/FrameFetchContext.cpp
+++ b/Source/core/loader/FrameFetchContext.cpp
@@ -162,15 +162,22 @@ ResourceRequestCachePolicy FrameFetchContext::resourceRequestCachePolicy(const R
         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;
     }