Add UMA to count the number of Google CAPTCHA pages shown and solved by users.

components/page_load_metrics/browser/metrics_web_contents_observer.cc

Index: components/page_load_metrics/browser/metrics_web_contents_observer.cc
diff --git a/components/page_load_metrics/browser/metrics_web_contents_observer.cc b/components/page_load_metrics/browser/metrics_web_contents_observer.cc
index c8bd56ac526e7eb390799443b470c1957289b9f3..34a91246783576b442663487a16ff69b5ea757a3 100644
--- a/components/page_load_metrics/browser/metrics_web_contents_observer.cc
+++ b/components/page_load_metrics/browser/metrics_web_contents_observer.cc
@@ -7,6 +7,8 @@
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/metrics/user_metrics.h"
+#include "base/metrics/user_metrics_action.h"
 #include "components/page_load_metrics/browser/page_load_metrics_macros.h"
 #include "components/page_load_metrics/common/page_load_metrics_messages.h"
 #include "components/page_load_metrics/common/page_load_timing.h"
@@ -119,6 +121,14 @@ uint64_t RapporHistogramBucketIndex(const base::TimeDelta& time) {
 
 }  // namespace
 
+bool IsGoogleCaptcha(const GURL& url) {
+  return (base::StartsWith(url.host(), "ipv4.google.",
+                           base::CompareCase::SENSITIVE)
+          || base::StartsWith(url.host(), "ipv6.google.",
+                              base::CompareCase::SENSITIVE))
+      && base::StartsWith(url.path(), "/sorry", base::CompareCase::SENSITIVE);
+}
+
 PageLoadTracker::PageLoadTracker(
     bool in_foreground,
     rappor::RapporService* const rappor_service,
@@ -439,6 +449,10 @@ void MetricsWebContentsObserver::DidStartNavigation(
 
 void MetricsWebContentsObserver::DidFinishNavigation(
     content::NavigationHandle* navigation_handle) {
+  if (IsGoogleCaptcha(navigation_handle->GetURL())) {
+    RecordAction(base::UserMetricsAction("GoogleCaptchaShown"));
+  }
+
   if (!navigation_handle->IsInMainFrame())
     return;
 
@@ -481,6 +495,13 @@ void MetricsWebContentsObserver::DidFinishNavigation(
   committed_load_->Commit(navigation_handle);
 }
 
+void MetricsWebContentsObserver::DidRedirectNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (IsGoogleCaptcha(navigation_handle->GetReferrer().url)) {
+    RecordAction(base::UserMetricsAction("GoogleCaptchaSolved"));
+  }
+}
+
 void MetricsWebContentsObserver::WasShown() {
   in_foreground_ = true;
   if (committed_load_)