Add metrics for tracking UX impact of non-static CLD data providers

chrome/renderer/translate/translate_helper.cc

Index: chrome/renderer/translate/translate_helper.cc
diff --git a/chrome/renderer/translate/translate_helper.cc b/chrome/renderer/translate/translate_helper.cc
index cffcfc55d92e040870ff44f43a00362d74e1cde9..587a38194082f0f1d11e0deb58f162110675fba9 100644
--- a/chrome/renderer/translate/translate_helper.cc
+++ b/chrome/renderer/translate/translate_helper.cc
@@ -8,6 +8,7 @@
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/user_metrics_action.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ -17,6 +18,7 @@
 #include "components/translate/core/common/translate_metrics.h"
 #include "components/translate/core/common/translate_util.h"
 #include "components/translate/core/language_detection/language_detection_util.h"
+#include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/render_view.h"
 #include "extensions/common/constants.h"
 #include "extensions/renderer/extension_groups.h"
@@ -45,6 +47,48 @@ using blink::WebString;
 using blink::WebVector;
 using blink::WebView;
 
+// Note on metrics:
+//
+// This class provides metrics that allow tracking the user experience impact
+// of non-static CldDataProvider implementations. For background on the data
+// providers, please refer to the following documentation:
+// http://www.chromium.org/developers/how-tos/compact-language-detector-cld-data-source-configuration
+//
+// Available metrics:
+// 1. Translate.LanguageDetectionOnTime
+//      Recorded if PageCaptured(...) is invoked after CLD is available.
+//      This is the ideal case, indicating that CLD is available before it is
+//      needed.
+// 2. Translate.LanguageDetectionDeferred
+//      Recorded if PageCaptured(...) is invoked before CLD is available.
+//      Sub-optimal case indicating that CLD wasn't available when it was
+//      needed, so the request for detection has been deferred until CLD is
+//      available or until the user navigates to a different page.
+// 3. Translate.LanguageDetectionLate
+//      Recorded if CLD becomes available after a language detection request
+//      was deferred as above in (2), but before the user navigated to a
+//      different page. Language detection is ultimately completed, it just
+//      didn't happen on time.
+//
+// Note that there is NOT a metric that records the number of times that
+// language detection had to be aborted because CLD never became available in
+// time. This is because there is no reasonable way to cover all the cases
+// under which this could occur, particularly the destruction of the renderer
+// for which this object was created. However, this value can be synthetically
+// derived, using the logic below.
+//
+// Every page load that triggers language detection will result in the
+// recording of exactly one of the first two metrics in the list above:
+// Translate.LanguageDetectionOnTime or Translate.LanguageDetectionDeferred.
+// If CLD is available in time to satisfy the request, the third metric
+// (Translate.LanguageDetectionLate) will be recorded; thus, the number of
+// times when language detection ultimately fails because CLD isn't ever
+// available is implied as the number of times that detection is deferred minus
+// the number of times that language detection is late. Note that this, too,
+// is not necessarily 100% relevant: some renderer process are so short-lived
+// that language detection wouldn't have been relevant anywaysm and so a failure

[Andrew Hayden (chromium.org), 2014/07/14 14:24:13]

"anywaysm" -> "anyways,"

[simonb1, 2014/07/14 16:23:48]

"anyways" -> "anyway" :-)
http://www.dailywritingtips.com/anyway-any-way-or-anyways/

+// to detect the language in a timely manner might be completely innocuous.
+
 namespace {
 
 // The delay in milliseconds that we'll wait before checking to see if the
@@ -88,7 +132,6 @@ TranslateHelper::TranslateHelper(content::RenderView* render_view)
 
 TranslateHelper::~TranslateHelper() {
   CancelPendingTranslation();
-  CancelCldDataPolling();
 }
 
 void TranslateHelper::PrepareForUrl(const GURL& url) {
@@ -140,17 +183,28 @@ void TranslateHelper::PageCapturedImpl(int page_seq_no,
   if (!main_frame || page_seq_no_ != page_seq_no)
     return;
 
-  // TODO(andrewhayden): UMA insertion point here: Track if data is available.
-  // TODO(andrewhayden): Retry insertion point here, retry till data available.
   if (!cld_data_provider_->IsCldDataAvailable()) {
     // We're in dynamic mode and CLD data isn't loaded. Retry when CLD data
     // is loaded, if ever.
     deferred_page_capture_ = true;
     deferred_page_seq_no_ = page_seq_no;
     deferred_contents_ = contents;
+    content::RenderThread::Get()->RecordAction(
+        base::UserMetricsAction("Translate.LanguageDetectionDeferred"));
     return;
   }
 
+  if (deferred_page_seq_no_ == -1) {
+    // CLD data was available before language detection was requested.
+    content::RenderThread::Get()->RecordAction(
+        base::UserMetricsAction("Translate.LanguageDetectionOnTime"));
+  } else {
+    // This is a request that was triggered because CLD data is now available
+    // and was previously deferred.
+    content::RenderThread::Get()->RecordAction(
+        base::UserMetricsAction("Translate.LanguageDetectionLate"));
+  }
+
   WebDocument document = main_frame->document();
   std::string content_language = document.contentLanguage().utf8();
   WebElement html_element = document.documentElement();