Refactor ResourceHandler API.

content/browser/loader/mojo_async_resource_handler.cc

Index: content/browser/loader/mojo_async_resource_handler.cc
diff --git a/content/browser/loader/mojo_async_resource_handler.cc b/content/browser/loader/mojo_async_resource_handler.cc
index 1288fe45136fb67142fa4ca4383a058c83eb14e9..9114570ff2652da150e380878e3d3af411c942aa 100644
--- a/content/browser/loader/mojo_async_resource_handler.cc
+++ b/content/browser/loader/mojo_async_resource_handler.cc
@@ -125,15 +125,15 @@ MojoAsyncResourceHandler::~MojoAsyncResourceHandler() {
     rdh_->FinishedWithResourcesForRequest(request());
 }
 
-bool MojoAsyncResourceHandler::OnRequestRedirected(
+void MojoAsyncResourceHandler::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     ResourceResponse* response,
-    bool* defer) {
+    bool* defer_or_cancel) {
   // Unlike OnResponseStarted, OnRequestRedirected will NOT be preceded by
   // OnWillRead.
   DCHECK(!shared_writer_);
 
-  *defer = true;
+  *defer_or_cancel = true;
   request()->LogBlockedBy("MojoAsyncResourceHandler");
   did_defer_on_redirect_ = true;
 
@@ -146,11 +146,10 @@ bool MojoAsyncResourceHandler::OnRequestRedirected(
   // and hopefully those will eventually all be owned by the browser. It's
   // possible this is still needed while renderer-owned ones exist.
   url_loader_client_->OnReceiveRedirect(redirect_info, response->head);
-  return true;
 }
 
-bool MojoAsyncResourceHandler::OnResponseStarted(ResourceResponse* response,
-                                                 bool* defer) {
+void MojoAsyncResourceHandler::OnResponseStarted(ResourceResponse* response,
+                                                 bool* defer_or_cancel) {
   const ResourceRequestInfoImpl* info = GetRequestInfo();
 
   if (rdh_->delegate()) {
@@ -164,13 +163,15 @@ bool MojoAsyncResourceHandler::OnResponseStarted(ResourceResponse* response,
   response->head.response_start = base::TimeTicks::Now();
   sent_received_response_message_ = true;
   url_loader_client_->OnReceiveResponse(response->head);
-  return true;
 }
 
-bool MojoAsyncResourceHandler::OnWillStart(const GURL& url, bool* defer) {
-  return true;
+void MojoAsyncResourceHandler::OnWillStart(const GURL& url,
+                                           bool* defer_or_cancel) {
+  return;
 }
 
+// TODO(mmenke): The implementation of this method and OnReadComplete is very
+// unwieldy. Allow OnWillRead to complete asynchronously and clean things up.
 bool MojoAsyncResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
                                           int* buf_size,
                                           int min_size) {
@@ -223,37 +224,46 @@ bool MojoAsyncResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
   return true;
 }
 
-bool MojoAsyncResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
+void MojoAsyncResourceHandler::OnReadCompleted(int bytes_read,
+                                               bool* defer_or_cancel) {
   DCHECK_GE(bytes_read, 0);
   DCHECK(buffer_);
 
   if (!bytes_read)
-    return true;
+    return;
 
   if (is_using_io_buffer_not_from_writer_) {
     // Couldn't allocate a buffer on the data pipe in OnWillRead.
     DCHECK_EQ(0u, buffer_bytes_read_);
     buffer_bytes_read_ = bytes_read;
-    if (!CopyReadDataToDataPipe(defer))
-      return false;
-    if (*defer) {
+    if (!CopyReadDataToDataPipe(defer_or_cancel)) {
+      controller()->Cancel();
+      *defer_or_cancel = true;
+      return;
+    }
+    if (*defer_or_cancel) {
       request()->LogBlockedBy("MojoAsyncResourceHandler");
       did_defer_on_writing_ = true;
     }
-    return true;
+    return;
   }
 
-  if (EndWrite(bytes_read) != MOJO_RESULT_OK)
-    return false;
+  if (EndWrite(bytes_read) != MOJO_RESULT_OK) {
+    controller()->Cancel();
+    *defer_or_cancel = true;
+    return;
+  }
   // Allocate a buffer for the next OnWillRead call here, because OnWillRead
   // doesn't have |defer| parameter.
-  if (!AllocateWriterIOBuffer(&buffer_, defer))
-    return false;
-  if (*defer) {
+  if (!AllocateWriterIOBuffer(&buffer_, defer_or_cancel)) {
+    controller()->Cancel();
+    *defer_or_cancel = true;
+    return;
+  }
+  if (*defer_or_cancel) {
     request()->LogBlockedBy("MojoAsyncResourceHandler");
     did_defer_on_writing_ = true;
   }
-  return true;
 }
 
 void MojoAsyncResourceHandler::OnDataDownloaded(int bytes_downloaded) {