Add metrics for YouTube Flash embed rewrite.

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index a59a8a81003b2da4567b721f10438e91b4aa946d..6772031a7392acc7a3504c46536ac4c7dfec5725 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -185,6 +185,16 @@ using extensions::Extension;
 
 namespace {
 
+enum YouTubeRewriteStatus {
+  SUCCESS = 0,
+  SUCCESS_PARAMS_REWRITE = 1,
+  SUCCESS_ENABLEJSAPI = 2,
+  FAILURE_ENABLEJSAPI = 3,
+  NUM_PLUGIN_ERROR  // should be kept last
+};
+
+const char kFlashYouTubeRewriteUMA[] = "Plugin.Flash.YouTubeRewrite";
+
 // Whitelist PPAPI for Android Runtime for Chromium. (See crbug.com/383937)
 #if defined(ENABLE_PLUGINS)
 const char* const kPredefinedAllowedCameraDeviceOrigins[] = {
@@ -1432,8 +1442,11 @@ GURL ChromeContentRendererClient::OverrideFlashEmbedWithHTML(const GURL& url) {
   // We don't modify any URLs that contain the enablejsapi=1 parameter
   // since the page may be interacting with the YouTube Flash player in
   // Javascript and we don't want to break working content.
-  if (corrected_url.query().find("enablejsapi=1") != std::string::npos)
+  if (corrected_url.query().find("enablejsapi=1") != std::string::npos) {
+    UMA_HISTOGRAM_ENUMERATION(kFlashYouTubeRewriteUMA, FAILURE_ENABLEJSAPI,

[Alexei Svitkine (slow), 2016/08/04 14:31:18]

UMA macros expand to a lot of code. Please avoid the duplication by making a
helper function for logging this histogram.

[kdsilva, 2016/08/04 18:28:52]

Done.

+                              NUM_PLUGIN_ERROR);
     return GURL();
+  }
 
   // Change the path to use the YouTube HTML5 API
   std::string path = corrected_url.path();
@@ -1442,5 +1455,8 @@ GURL ChromeContentRendererClient::OverrideFlashEmbedWithHTML(const GURL& url) {
   url::Replacements<char> r;
   r.SetPath(path.c_str(), url::Component(0, path.length()));
 
+  UMA_HISTOGRAM_ENUMERATION(kFlashYouTubeRewriteUMA,
+                            invalid_url ? SUCCESS_PARAMS_REWRITE : SUCCESS,
+                            NUM_PLUGIN_ERROR);
   return corrected_url.ReplaceComponents(r);
 }