Record if the navigation's initiator is available.

In NavigationRequest::BeginNavigation(), records whether the
navigation's initiator can be found using its ID or not.

We suspect not finding it is a very rare event. This histogram will help
us figure out what kind of solution should be used to support
PolicyContainer for this edge case.

Bug:1129416

Change-Id: I501bf0150935679667d5bd2a4cc351a70b6653ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2416450Reviewed-by: Camille Lamy <clamy@chromium.org>
Reviewed-by: Pâris Meuleman <pmeuleman@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Antonio Sartori <antoniosartori@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812124}

content/browser/navigation_browsertest.cc

@@ -13,6 +13,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/bind_test_util.h"
+#include "base/test/metrics/histogram_tester.h"
 #include "base/test/scoped_feature_list.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/thread_restrictions.h"
@@ -3788,4 +3789,46 @@ IN_PROC_BROWSER_TEST_F(DocumentPolicyBrowserTest,
   EXPECT_FALSE(last_metadata.is_scroll_offset_at_top);
 }
 
+IN_PROC_BROWSER_TEST_F(NavigationBrowserTest, RecordInitiatorRfh) {
+  base::HistogramTester histograms;
+  GURL url(embedded_test_server()->GetURL("/empty.html"));
+
+  // First navigation with no initiator.
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+  ShellAddedObserver new_shell_observer;
+  {
+    std::vector<base::Bucket> samples =
+        histograms.GetAllSamples("Navigation.InitiatorRFH");
+    EXPECT_EQ(1u, samples.size());
+    EXPECT_EQ(1, samples[0].count);  // InitiatorRFH::NONE
+  }
+
+  // Second navigation with an initiator and a matching RenderFrameHost.
+  EXPECT_TRUE(ExecJs(shell(), JsReplace("window.open($1);", url)));
+  Shell* openee_shell = new_shell_observer.GetShell();
+  {
+    std::vector<base::Bucket> samples =
+        histograms.GetAllSamples("Navigation.InitiatorRFH");
+    EXPECT_EQ(1, samples[0].count);  // InitiatorRFH::NONE
+    EXPECT_EQ(1, samples[1].count);  // InitiatorRFH::EXISTING_RFH
+  }
+
+  // Third navigation with an initiator and no matching RenderFrameHost.
+  TestNavigationObserver observer(shell()->web_contents());
+  EXPECT_TRUE(ExecJs(openee_shell, R"(
+    onunload = () => opener.location.href = "about:blank";
+  )"));
+  openee_shell->Close();
+  observer.Wait();
+
+  {
+    std::vector<base::Bucket> samples =
+        histograms.GetAllSamples("Navigation.InitiatorRFH");
+    EXPECT_EQ(3u, samples.size());
+    EXPECT_EQ(1, samples[0].count);  // InitiatorRFH::NONE
+    EXPECT_EQ(1, samples[1].count);  // InitiatorRFH::EXISTING_RFH
+    EXPECT_EQ(1, samples[2].count);  // InitiatorRFH::DELETED_RFH
+  }
+}
+
 }  // namespace content

content/browser/renderer_host/navigation_request.cc

@@ -728,6 +728,28 @@ url::Origin GetOriginForURLLoaderFactoryUnchecked(
       common_params.initiator_origin.value_or(url::Origin()));
 }
 
+void RecordInitiatorRFH(GlobalFrameRoutingId id) {
+  // Corresponds to the "InitiatorRFH" histogram enumeration type in
+  // tools/metrics/histograms/enums.xml.
+  //
+  // DO NOT REORDER OR CHANGE THE MEANING OF THESE VALUES.
+  enum InitiatorRFH {
+    NONE = 0,
+    EXISTING_RFH = 1,
+    DELETED_RFH = 2,
+
+    kMaxValue = DELETED_RFH,
+  } value;
+
+  if (!id)
+    value = NONE;
+  else if (RenderFrameHost::FromID(id))
+    value = EXISTING_RFH;
+  else
+    value = DELETED_RFH;
+  UMA_HISTOGRAM_ENUMERATION("Navigation.InitiatorRFH", value);
+}
+
 }  // namespace
 
 // static
@@ -1076,6 +1098,8 @@ NavigationRequest::NavigationRequest(
                                     base::trace_event::ToTracedValue(this));
   TRACE_EVENT_NESTABLE_ASYNC_BEGIN0("navigation", "Initializing",
                                     navigation_id_);
+  RecordInitiatorRFH(GetInitiatorRoutingId());
+
   NavigationControllerImpl* controller = GetNavigationController();
 
   if (frame_entry) {

tools/metrics/histograms/enums.xml

@@ -36821,6 +36821,16 @@ Called by update_gpu_driver_bug_workaround_entries.py.-->
   <int value="3" label="Has access"/>
 </enum>
 
+<enum name="InitiatorRFH">
+  <int value="0" label="No initiator"/>
+  <int value="1"
+      label="Initiator RenderFrameHost existed when the NavigationRequest was
+             created"/>
+  <int value="2"
+      label="Initiator RenderFrameHost did not exist anymore when the
+             NavigationRequest was created"/>
+</enum>
+
 <enum name="InjectedAdType">
   <int value="0" label="Invalid"/>
   <int value="1" label="IFrame"/>

tools/metrics/histograms/histograms_xml/navigation/histograms.xml

@@ -256,6 +256,18 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="Navigation.InitiatorRFH" enum="InitiatorRFH"
+    expires_after="M89">
+  <owner>arthursonzogni@chromium.org</owner>
+  <owner>pmeuleman@chromium.org</owner>
+  <owner>antoniosartori@chromium.org</owner>
+  <owner>clamy@chromium.org</owner>
+  <summary>
+    Count how many NavigationRequests can find their associated initiator's
+    RenderFrameHost.
+  </summary>
+</histogram>
+
 <histogram name="Navigation.IOSNullContextInDidFailProvisionalNavigation"
     enum="Boolean" expires_after="M85">
   <owner>ajuma@chromium.org</owner>