Prerender: deprecate kEmbedderTriggeredAndDestroyed

This type was introduced by I816113d3792c32cfe19bafd5e669c83b94b52053.
Checking its usage seems to be the same as TriggerDestroyed, as the
trigger type has already told us the trigger. So, to simplify
PrerenderHost::FinalStatus, we can replace
kEmbedderTriggeredAndDestroyed with TriggerDestroyed.

Bug: N/A
Change-Id: I8218bc1635385320eb1fbed91db87412fd4eea58
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3789540
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Lingqi Chi <lingqi@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Danil Somsikov <dsv@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1034966}

chrome/browser/preloading/prerender/omnibox_prerender_browsertest.cc

@@ -583,7 +583,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderOmniboxSearchSuggestionExpiryBrowserTest,
   histogram_tester.ExpectUniqueSample(
       "Prerender.Experimental.PrerenderHostFinalStatus.Embedder_"
       "DefaultSearchEngine",
-      /*PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed*/ 35, 1);
+      /*PrerenderHost::FinalStatus::kTriggerDestroyed*/ 16, 1);
 
   // Select the prerender hint. The prerendered result has been deleted, so
   // browser loads the search result over again.
@@ -628,7 +628,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderOmniboxSearchSuggestionExpiryBrowserTest,
   histogram_tester.ExpectUniqueSample(
       "Prerender.Experimental.PrerenderHostFinalStatus.Embedder_"
       "DefaultSearchEngine",
-      /*PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed*/ 35, 1);
+      /*PrerenderHost::FinalStatus::kTriggerDestroyed*/ 16, 1);
 
   // Nothing should be recorded. Because there is no new navigation nor new
   // search suggestion.

content/browser/devtools/protocol/page_handler.cc

@@ -1421,8 +1421,6 @@ Page::PrerenderFinalStatus PrerenderFinalStatusToProtocol(
     case PrerenderHost::FinalStatus::kEmbedderTriggeredAndCrossOriginRedirected:
       return Page::PrerenderFinalStatusEnum::
           EmbedderTriggeredAndCrossOriginRedirected;
-    case PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed:
-      return Page::PrerenderFinalStatusEnum::EmbedderTriggeredAndDestroyed;
     case PrerenderHost::FinalStatus::kEmbedderTriggeredAndSameOriginRedirected:
       return Page::PrerenderFinalStatusEnum::
           EmbedderTriggeredAndSameOriginRedirected;

content/browser/preloading/prerender/prerender_handle_impl.cc

@@ -16,8 +16,7 @@ PrerenderHandleImpl::PrerenderHandleImpl(
       frame_tree_node_id_(frame_tree_node_id),
       prerendering_url_(prerendering_url) {
   DCHECK(!prerendering_url_.is_empty());
-  // PrerenderHandleImpl is now designed only for embedder triggers (e.g.,
-  // recording kEmbedderTriggeredAndDestroyed on the destructor). If you use
+  // PrerenderHandleImpl is now designed only for embedder triggers. If you use
   // this handle for other triggers, please make sure to update the logging etc.
   auto* prerender_host =
       prerender_host_registry_->FindNonReservedHostById(frame_tree_node_id);
@@ -28,8 +27,7 @@ PrerenderHandleImpl::PrerenderHandleImpl(
 PrerenderHandleImpl::~PrerenderHandleImpl() {
   if (prerender_host_registry_) {
     prerender_host_registry_->CancelHost(
-        frame_tree_node_id_,
-        PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed);
+        frame_tree_node_id_, PrerenderHost::FinalStatus::kTriggerDestroyed);
   }
 }
 

content/browser/preloading/prerender/prerender_host.cc

@@ -644,9 +644,8 @@ void PrerenderHost::SetFailureReason(FinalStatus status) {
     // explicitly do not propagate failure reasons if the prerender was actually
     // successful (kActivated), or if prerender was successfully prepared but
     // then destroyed because it wasn't needed for a subsequent navigation
-    // (kTriggerDestroyed, kEmbedderTriggeredAndDestroyed).
+    // (kTriggerDestroyed).
     case FinalStatus::kActivated:
-    case FinalStatus::kEmbedderTriggeredAndDestroyed:
     case FinalStatus::kTriggerDestroyed:
       return;
     case FinalStatus::kDestroyed:

content/browser/preloading/prerender/prerender_host.h

@@ -92,7 +92,9 @@ class CONTENT_EXPORT PrerenderHost : public WebContentsObserver {
     // kEmbedderTriggeredAndRedirected = 32,
     kEmbedderTriggeredAndSameOriginRedirected = 33,
     kEmbedderTriggeredAndCrossOriginRedirected = 34,
-    kEmbedderTriggeredAndDestroyed = 35,
+    // Deprecated. This has the same meaning as kTriggerDestroyed because the
+    // metric's name includes trigger type.
+    // kEmbedderTriggeredAndDestroyed = 35,
     kMemoryLimitExceeded = 36,
     kFailToGetMemoryUsage = 37,
     kDataSaverEnabled = 38,

content/browser/preloading/prerender/prerender_internals_handler_impl.cc

@@ -76,8 +76,6 @@ const char* FinalStatusToString(PrerenderHost::FinalStatus final_status) {
       return "EmbedderTriggeredAndSameOriginRedirected";
     case PrerenderHost::FinalStatus::kEmbedderTriggeredAndCrossOriginRedirected:
       return "EmbedderTriggeredAndCrossOriginRedirected";
-    case PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed:
-      return "EmbedderTriggeredAndDestroyed";
     case PrerenderHost::FinalStatus::kMemoryLimitExceeded:
       return "MemoryLimitExceeded";
     case PrerenderHost::FinalStatus::kFailToGetMemoryUsage:

third_party/blink/public/devtools_protocol/browser_protocol.pdl

@@ -8459,7 +8459,6 @@ domain Page
       TriggerBackgrounded
       EmbedderTriggeredAndSameOriginRedirected
       EmbedderTriggeredAndCrossOriginRedirected
-      EmbedderTriggeredAndDestroyed
       MemoryLimitExceeded
       # Prerenders can be cancelled when Chrome uses excessive memory. This is
       # recorded when it fails to get the memory usage.

tools/metrics/histograms/enums.xml

@@ -78939,7 +78939,7 @@ Called by update_net_trust_anchors.py.-->
   <int value="32" label="kEmbedderTriggeredAndRedirected"/>
   <int value="33" label="kEmbedderTriggeredAndSameOriginRedirected"/>
   <int value="34" label="kEmbedderTriggeredAndCrossOriginRedirected"/>
-  <int value="35" label="kEmbedderTriggeredAndDestroyed"/>
+  <int value="35" label="kEmbedderTriggeredAndDestroyed (obsoleted)"/>
   <int value="36" label="kMemoryLimitExceeded"/>
   <int value="37" label="kFailToGetMemoryUsage"/>
   <int value="38" label="kDataSaverEnabled"/>