[Blob] Added error reporting metrics to invalid message errors.

content/browser/blob_storage/blob_dispatcher_host.cc

Index: content/browser/blob_storage/blob_dispatcher_host.cc
diff --git a/content/browser/blob_storage/blob_dispatcher_host.cc b/content/browser/blob_storage/blob_dispatcher_host.cc
index ba15620d8fec4d289beb2801fbf18baa2a56dbd9..22bf25d79c4a38757a070493fce5dc6d6ea8cd6c 100644
--- a/content/browser/blob_storage/blob_dispatcher_host.cc
+++ b/content/browser/blob_storage/blob_dispatcher_host.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "base/bind.h"
+#include "base/metrics/histogram.h"

[Mark P, 2016/04/19 19:34:52]

Prefer histogram_macros.h

 #include "content/browser/bad_message.h"
 #include "content/browser/fileapi/chrome_blob_storage_context.h"
 #include "content/common/fileapi/webblob_messages.h"
@@ -209,6 +210,7 @@ void BlobDispatcherHost::OnIncrementBlobRefCount(const std::string& uuid) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   BlobStorageContext* context = this->context();
   if (uuid.empty() || !context->registry().HasEntry(uuid)) {
+    UMA_HISTOGRAM_BOOLEAN("Storage.Blob.InvalidReferenceInc", true);

[Mark P, 2016/04/19 19:34:52]

If you're only emitting true to this histogram, why don't you simply do
Storage.Blob.InvalidReference and have true = Increment and false = Decrement?

     bad_message::ReceivedBadMessage(
         this, bad_message::BDH_INVALID_REFCOUNT_OPERATION);
     return;
@@ -220,6 +222,7 @@ void BlobDispatcherHost::OnIncrementBlobRefCount(const std::string& uuid) {
 void BlobDispatcherHost::OnDecrementBlobRefCount(const std::string& uuid) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (uuid.empty() || !IsInUseInHost(uuid)) {
+    UMA_HISTOGRAM_BOOLEAN("Storage.Blob.InvalidReferenceDec", true);
     bad_message::ReceivedBadMessage(
         this, bad_message::BDH_INVALID_REFCOUNT_OPERATION);
     return;
@@ -249,6 +252,7 @@ void BlobDispatcherHost::OnRegisterPublicBlobURL(const GURL& public_url,
   BlobStorageContext* context = this->context();
   if (uuid.empty() || !IsInUseInHost(uuid) ||
       context->registry().IsURLMapped(public_url)) {
+    UMA_HISTOGRAM_BOOLEAN("Storage.Blob.InvalidURLRegister", true);

[Mark P, 2016/04/19 19:34:52]

analogous comment here

     bad_message::ReceivedBadMessage(this,
                                     bad_message::BDH_INVALID_URL_OPERATION);
     return;
@@ -260,6 +264,7 @@ void BlobDispatcherHost::OnRegisterPublicBlobURL(const GURL& public_url,
 void BlobDispatcherHost::OnRevokePublicBlobURL(const GURL& public_url) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (!IsUrlRegisteredInHost(public_url)) {
+    UMA_HISTOGRAM_BOOLEAN("Storage.Blob.InvalidURLRevoke", true);
     bad_message::ReceivedBadMessage(this,
                                     bad_message::BDH_INVALID_URL_OPERATION);
     return;