Make DownloadHistory observe manager, items

content/browser/download/base_file.cc

Index: content/browser/download/base_file.cc
diff --git a/content/browser/download/base_file.cc b/content/browser/download/base_file.cc
index 1d5d1e2e1ba3318bd7ae74a51a152d1d9508acbe..9de9538c5e351d18965702f7d97649d4e0d6e1c0 100644
--- a/content/browser/download/base_file.cc
+++ b/content/browser/download/base_file.cc
@@ -265,7 +265,7 @@ net::Error BaseFile::Initialize() {
 
 net::Error BaseFile::AppendDataToFile(const char* data, size_t data_len) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-  DCHECK(!detached_);
+  if (detached_) return net::ERR_INVALID_HANDLE;
 
   // NOTE(benwells): The above DCHECK won't be present in release builds,
   // so we log any occurences to see how common this error is in the wild.
@@ -402,7 +402,7 @@ void BaseFile::Detach() {
 
 void BaseFile::Cancel() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-  DCHECK(!detached_);
+  if (detached_) return;
 
   bound_net_log_.AddEvent(net::NetLog::TYPE_CANCELLED);
 
@@ -425,7 +425,7 @@ void BaseFile::Finish() {
 }
 
 bool BaseFile::GetHash(std::string* hash) {
-  DCHECK(!detached_);
+  if (detached_) return false;
   hash->assign(reinterpret_cast<const char*>(sha256_hash_),
                sizeof(sha256_hash_));
   return (calculate_hash_ && !in_progress());
@@ -460,7 +460,7 @@ bool BaseFile::IsEmptyHash(const std::string& hash) {
 
 void BaseFile::AnnotateWithSourceInformation() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
-  DCHECK(!detached_);
+  if (detached_) return;
 
 #if defined(OS_WIN)
   // Sets the Zone to tell Windows that this file comes from the internet.