Fix a pair of ResourceLoader cancellation/error bugs.

content/browser/loader/resource_loader.cc

Index: content/browser/loader/resource_loader.cc
diff --git a/content/browser/loader/resource_loader.cc b/content/browser/loader/resource_loader.cc
index 0b3833a655ec3c9a6f44b7826de333f460f26f68..d944ea9a5e59175cca7ae78646f93242eabba6b8 100644
--- a/content/browser/loader/resource_loader.cc
+++ b/content/browser/loader/resource_loader.cc
@@ -350,13 +350,13 @@ void ResourceLoader::OnResponseStarted(net::URLRequest* unused) {
 
   CompleteResponseStarted();
 
-  if (is_deferred())
+  // If the handler deferred the request, it will resume the request later. If
+  // the request was cancelled, the request will call back into |this| with a
+  // bogus read completed error.
+  if (is_deferred() || !request_->status().is_success())
     return;
 
-  if (request_->status().is_success())
-    StartReading(false);  // Read the first chunk.
-  else
-    ResponseCompleted();
+  StartReading(false);  // Read the first chunk.
 }
 
 void ResourceLoader::OnReadCompleted(net::URLRequest* unused, int bytes_read) {
@@ -375,12 +375,9 @@ void ResourceLoader::OnReadCompleted(net::URLRequest* unused, int bytes_read) {
   CompleteRead(bytes_read);
 
   // If the handler cancelled or deferred the request, do not continue
-  // processing the read. If cancelled, the URLRequest has already been
-  // cancelled and will schedule an erroring OnReadCompleted later. If deferred,
-  // do nothing until resumed.
-  //
-  // Note: if bytes_read is 0 (EOF) and the handler defers, resumption will call
-  // ResponseCompleted().
+  // processing the read. If canceled, either the request will call into |this|
+  // with a bogus read error, or, if the request was completed, a task posted
+  // from ResourceLoader::CancelREquestInternal will run OnResponseCompleted.
   if (is_deferred() || !request_->status().is_success())
     return;
 
@@ -562,7 +559,8 @@ void ResourceLoader::StartReading(bool is_continuation) {
   ReadMore(&bytes_read);
 
   // If IO is pending, wait for the URLRequest to call OnReadCompleted.
-  if (request_->status().is_io_pending())
+  // On error or cancellation, wait for notification of failure.
+  if (request_->status().is_io_pending() || !request_->status().is_success())
     return;
 
   if (!is_continuation || bytes_read <= 0) {