Fix the crash if a download starts before we have the plugin list. The fix is to make ResourceDispatcherHost support a handler pausing a request in its OnResponseStarted callback.

Note I didn't find any way of testing the resource handler code, so I didn't know how to add a good test for this.

BUG=19414
Review URL: http://codereview.chromium.org/173037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@23769 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 34 insertions, 11 deletions

diff --git a/chrome/browser/renderer_host/resource_dispatcher_host.cc b/chrome/browser/renderer_host/resource_dispatcher_host.cc
index 9b32684..7e5cded 100644
--- a/chrome/browser/renderer_host/resource_dispatcher_host.cc
+++ b/chrome/browser/renderer_host/resource_dispatcher_host.cc
@@ -1054,15 +1054,13 @@ void ResourceDispatcherHost::OnResponseStarted(URLRequest* request) {
     if (!CompleteResponseStarted(request)) {
       CancelRequest(info->process_id, info->request_id, false);
     } else {
-      // Start reading.
-      int bytes_read = 0;
-      if (Read(request, &bytes_read)) {
-        OnReadCompleted(request, bytes_read);
-      } else if (!request->status().is_io_pending()) {
-        DCHECK(!info->is_paused);
-        // If the error is not an IO pending, then we're done reading.
-        OnResponseCompleted(request);
+      // Check if the handler paused the request in their OnResponseStarted.
+      if (PauseRequestIfNeeded(info)) {
+        RESOURCE_LOG("OnResponseStarted pausing2: " << request->url().spec());
+        return;
       }
+
+      StartReading(request);
     }
   } else {
     OnResponseCompleted(request);
@@ -1102,6 +1100,7 @@ bool ResourceDispatcherHost::CompleteResponseStarted(URLRequest* request) {
   }
 
   NotifyResponseStarted(request, info->process_id);
+  info->called_on_response_started = true;
   return info->resource_handler->OnResponseStarted(info->request_id,
                                                    response.get());
 }
@@ -1278,10 +1277,27 @@ void ResourceDispatcherHost::ResumeRequest(const GlobalRequestID& request_id) {
 
   info->is_paused = false;
 
-  if (info->has_started_reading)
-    OnReadCompleted(i->second, info->paused_read_bytes);
-  else
+  if (info->called_on_response_started) {
+    if (info->has_started_reading) {
+      OnReadCompleted(i->second, info->paused_read_bytes);
+    } else {
+      StartReading(request);
+    }
+  } else {
     OnResponseStarted(i->second);
+  }
+}
+
+void ResourceDispatcherHost::StartReading(URLRequest* request) {
+  // Start reading.
+  int bytes_read = 0;
+  if (Read(request, &bytes_read)) {
+    OnReadCompleted(request, bytes_read);
+  } else if (!request->status().is_io_pending()) {
+    DCHECK(!ExtraInfoForRequest(request)->is_paused);
+    // If the error is not an IO pending, then we're done reading.
+    OnResponseCompleted(request);
+  }
 }
 
 bool ResourceDispatcherHost::Read(URLRequest* request, int* bytes_read) {
diff --git a/chrome/browser/renderer_host/resource_dispatcher_host.h b/chrome/browser/renderer_host/resource_dispatcher_host.h
index e36e97f..f7dc92e 100644
--- a/chrome/browser/renderer_host/resource_dispatcher_host.h
+++ b/chrome/browser/renderer_host/resource_dispatcher_host.h
@@ -105,6 +105,7 @@ class ResourceDispatcherHost : public URLRequest::Delegate {
           waiting_for_upload_progress_ack(false),
           memory_cost(0),
           is_paused(false),
+          called_on_response_started(false),
           has_started_reading(false),
           paused_read_bytes(0) {
     }
@@ -175,6 +176,9 @@ class ResourceDispatcherHost : public URLRequest::Delegate {
     // by the ResourceDispatcherHost, not the event handlers.
     bool is_paused;
 
+    // Whether we called OnResponseStarted for this request or not.
+    bool called_on_response_started;
+
     // Whether this request has started reading any bytes from the response
     // yet.  Will be true after the first (unpaused) call to Read.
     bool has_started_reading;
@@ -413,6 +417,9 @@ class ResourceDispatcherHost : public URLRequest::Delegate {
   // Resumes the given request by calling OnResponseStarted or OnReadCompleted.
   void ResumeRequest(const GlobalRequestID& request_id);
 
+  // Internal function to start reading for the first time.
+  void StartReading(URLRequest* request);
+
   // Reads data from the response using our internal buffer as async IO.
   // Returns true if data is available immediately, false otherwise.  If the
   // return value is false, we will receive a OnReadComplete() callback later.