Separate same domain and cross domain <link rel=...> prerenders for reporting.

chrome/browser/prerender/prerender_histograms.cc

Index: chrome/browser/prerender/prerender_histograms.cc
diff --git a/chrome/browser/prerender/prerender_histograms.cc b/chrome/browser/prerender/prerender_histograms.cc
index 5e75a03cef4eb5f2f4e4e699546b6a56382cd4e9..a7fa97f136a04c00d7e45f086a019800dab0fe8d 100644
--- a/chrome/browser/prerender/prerender_histograms.cc
+++ b/chrome/browser/prerender/prerender_histograms.cc
@@ -50,8 +50,10 @@ std::string GetHistogramName(Origin origin, uint8 experiment_id,
   switch (origin) {
     case ORIGIN_OMNIBOX:
       return ComposeHistogramName("omnibox", name);
-    case ORIGIN_LINK_REL_PRERENDER:
-      return ComposeHistogramName("web", name);
+    case ORIGIN_LINK_REL_PRERENDER_SAMEDOMAIN:
+      return ComposeHistogramName("websame", name);
+    case ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN:
+      return ComposeHistogramName("webcross", name);
     case ORIGIN_GWS_PRERENDER:  // Handled above.
     default:
       NOTREACHED();
@@ -101,10 +103,12 @@ bool OriginIsOmnibox(Origin origin) {
   } else if (experiment != kNoExperiment && \
              (origin != ORIGIN_GWS_PRERENDER || \
               experiment != recording_experiment)) { \
-  } else if (origin == ORIGIN_LINK_REL_PRERENDER) { \
-    HISTOGRAM; \
   } else if (origin == ORIGIN_OMNIBOX) { \
     HISTOGRAM; \
+  } else if (origin == ORIGIN_LINK_REL_PRERENDER_SAMEDOMAIN) { \
+    HISTOGRAM; \
+  } else if (origin == ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN) { \
+    HISTOGRAM; \
   } else if (experiment != kNoExperiment) { \
     HISTOGRAM; \
   } else { \
@@ -114,7 +118,7 @@ bool OriginIsOmnibox(Origin origin) {
 
 PrerenderHistograms::PrerenderHistograms()
     : last_experiment_id_(kNoExperiment),
-      last_origin_(ORIGIN_LINK_REL_PRERENDER),
+      last_origin_(ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN),
       origin_experiment_wash_(false),
       seen_any_pageload_(true),
       seen_pageload_started_after_prerender_(true) {
@@ -391,7 +395,7 @@ uint8 PrerenderHistograms::GetCurrentExperimentId() const {
 
 Origin PrerenderHistograms::GetCurrentOrigin() const {
   if (!WithinWindow())
-    return ORIGIN_LINK_REL_PRERENDER;
+    return ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN;

[dominich, 2012/09/13 20:03:36]

why is this the default here?

[gavinp, 2012/09/14 02:00:42]

Why was ORIGIN_LINK_REL_PRERENDER the default before?

[dominich, 2012/09/14 14:40:45]

I have no idea, but it seems very wrong to me. We probably don't have a
last_origin_ if we're within window, but we should then have a 'current origin'.
I think this is a bug, and I think we should fix it, given that we're now
looking to analyze the same/cross domain delta.

[gavinp, 2012/09/14 21:10:47]

I'm adding Timo to this review to explain, since I couldn't understand this code
when I read it. Timo, what should we do here?

On 2012/09/14 14:40:45, dominich wrote:

[mmenke, 2012/09/17 20:39:27]

I'm not Timo (Though I've always wanted to play him on TV), but I think now that
we allow multiple prerenders, this may be a rather dysfunctional function.  Some
places, at least, we can get the relevant origin directly from the prerender.

[gavinp, 2012/09/20 04:18:10]

Oh boy, I've now reviewed this code, and these histograms are really broken
right now, since this entire file operates using what amounts to global
variables.

I'm in the process of fixing them, but there's ten distinct PLTs in
"FirstFooAfterBarWithExtraQuux"...  I'm trying to decide how much to preserve
and how much to shred.

Timo, how many of these are you using? Which ones are most interesting?

   return last_origin_;
 }