Redirect HTML resource bytes directly to parser thread (Chrome side CL)

content/child/resource_dispatcher.cc

Index: content/child/resource_dispatcher.cc
diff --git a/content/child/resource_dispatcher.cc b/content/child/resource_dispatcher.cc
index f20e4dd6ddd7ebf25b97f865a8ae3a0e6554e2fe..a877bb54ad3aa236da55bd79c0245f2fdcfc79b3 100644
--- a/content/child/resource_dispatcher.cc
+++ b/content/child/resource_dispatcher.cc
@@ -19,6 +19,7 @@
 #include "content/child/request_info.h"
 #include "content/child/site_isolation_policy.h"
 #include "content/child/sync_load_response.h"
+#include "content/child/threaded_data_provider.h"
 #include "content/common/inter_process_time_ticks_converter.h"
 #include "content/common/resource_messages.h"
 #include "content/public/child/request_peer.h"
@@ -80,6 +81,8 @@ class IPCResourceLoaderBridge : public ResourceLoaderBridge {
   virtual void SetDefersLoading(bool value) OVERRIDE;
   virtual void DidChangePriority(net::RequestPriority new_priority,
                                  int intra_priority_value) OVERRIDE;
+  virtual bool AttachThreadedDataReceiver(
+      blink::WebThreadedDataReceiver* threaded_data_receiver) OVERRIDE;
   virtual void SyncLoad(SyncLoadResponse* response) OVERRIDE;
 
  private:
@@ -220,6 +223,17 @@ void IPCResourceLoaderBridge::DidChangePriority(
       request_id_, new_priority, intra_priority_value);
 }
 
+bool IPCResourceLoaderBridge::AttachThreadedDataReceiver(
+    blink::WebThreadedDataReceiver* threaded_data_receiver) {
+  if (request_id_ < 0) {
+    NOTREACHED() << "Trying to attach threaded receiver on unstarted request";
+    return false;
+  }
+
+  return dispatcher_->AttachThreadedDataReceiver(request_id_,
+                                                 threaded_data_receiver);
+}
+
 void IPCResourceLoaderBridge::SyncLoad(SyncLoadResponse* response) {
   if (request_id_ != -1) {
     NOTREACHED() << "Starting a request twice";
@@ -405,6 +419,7 @@ void ResourceDispatcher::OnReceivedData(int request_id,
   TRACE_EVENT0("loader", "ResourceDispatcher::OnReceivedData");
   DCHECK_GT(data_length, 0);
   PendingRequestInfo* request_info = GetPendingRequestInfo(request_id);
+  bool send_ack = true;
   if (request_info && data_length > 0) {
     CHECK(base::SharedMemory::IsHandleValid(request_info->buffer->handle()));
     CHECK_GE(request_info->buffer_size, data_offset + data_length);
@@ -416,9 +431,10 @@ void ResourceDispatcher::OnReceivedData(int request_id,
 
     base::TimeTicks time_start = base::TimeTicks::Now();
 
-    const char* data_ptr = static_cast<char*>(request_info->buffer->memory());
-    CHECK(data_ptr);
-    CHECK(data_ptr + data_offset);
+    const char* data_start = static_cast<char*>(request_info->buffer->memory());
+    CHECK(data_start);
+    CHECK(data_start + data_offset);
+    const char* data_ptr = data_start + data_offset;
 
     // Check whether this response data is compliant with our cross-site
     // document blocking policy. We only do this for the first packet.
@@ -426,22 +442,31 @@ void ResourceDispatcher::OnReceivedData(int request_id,
     if (request_info->site_isolation_metadata.get()) {
       request_info->blocked_response =
           SiteIsolationPolicy::ShouldBlockResponse(
-              request_info->site_isolation_metadata, data_ptr + data_offset,
-              data_length, &alternative_data);
+              request_info->site_isolation_metadata, data_ptr, data_length,
+              &alternative_data);
       request_info->site_isolation_metadata.reset();
-    }
 
-    // When the response is not blocked.
-    if (!request_info->blocked_response) {
-      request_info->peer->OnReceivedData(
-          data_ptr + data_offset, data_length, encoded_data_length);
-    } else if (alternative_data.size() > 0) {
-      // When the response is blocked, and when we have any alternative data to
+      // When the response is blocked we may have any alternative data to
       // send to the renderer. When |alternative_data| is zero-sized, we do not
       // call peer's callback.
-      request_info->peer->OnReceivedData(alternative_data.data(),
-                                         alternative_data.size(),
-                                         alternative_data.size());
+      if (request_info->blocked_response && !alternative_data.empty()) {
+        data_ptr = alternative_data.data();
+        data_length = alternative_data.size();
+        encoded_data_length = alternative_data.size();
+      }
+    }
+
+    if (!request_info->blocked_response || !alternative_data.empty()) {
+      if (request_info->threaded_data_provider) {
+        request_info->threaded_data_provider->OnReceivedDataOnForegroundThread(
+            data_ptr, data_length, encoded_data_length);
+        // A threaded data provider will take care of its own ACKing, as the
+        // data may be processed later on another thread.
+        send_ack = false;
+      } else {
+        request_info->peer->OnReceivedData(
+            data_ptr, data_length, encoded_data_length);
+      }
     }
 
     UMA_HISTOGRAM_TIMES("ResourceDispatcher.OnReceivedDataTime",
@@ -449,7 +474,8 @@ void ResourceDispatcher::OnReceivedData(int request_id,
   }
 
   // Acknowledge the reception of this data.
-  message_sender_->Send(new ResourceHostMsg_DataReceived_ACK(request_id));
+  if (send_ack)
+    message_sender_->Send(new ResourceHostMsg_DataReceived_ACK(request_id));
 }
 
 void ResourceDispatcher::OnDownloadedData(int request_id,
@@ -623,8 +649,21 @@ void ResourceDispatcher::DidChangePriority(int request_id,
       request_id, new_priority, intra_priority_value));
 }
 
+bool ResourceDispatcher::AttachThreadedDataReceiver(
+    int request_id, blink::WebThreadedDataReceiver* threaded_data_receiver) {
+  PendingRequestInfo* request_info = GetPendingRequestInfo(request_id);
+  DCHECK(request_info);
+  DCHECK(!request_info->threaded_data_provider);
+  request_info->threaded_data_provider = new ThreadedDataProvider(
+      request_id, threaded_data_receiver, request_info->buffer,
+      request_info->buffer_size);
+
+  return true;
+}
+
 ResourceDispatcher::PendingRequestInfo::PendingRequestInfo()
     : peer(NULL),
+      threaded_data_provider(NULL),
       resource_type(ResourceType::SUB_RESOURCE),
       is_deferred(false),
       download_to_file(false),
@@ -640,6 +679,7 @@ ResourceDispatcher::PendingRequestInfo::PendingRequestInfo(
     const GURL& request_url,
     bool download_to_file)
     : peer(peer),
+      threaded_data_provider(NULL),
       resource_type(resource_type),
       origin_pid(origin_pid),
       is_deferred(false),
@@ -650,7 +690,10 @@ ResourceDispatcher::PendingRequestInfo::PendingRequestInfo(
       request_start(base::TimeTicks::Now()),
       blocked_response(false) {}
 
-ResourceDispatcher::PendingRequestInfo::~PendingRequestInfo() {}
+ResourceDispatcher::PendingRequestInfo::~PendingRequestInfo() {
+  if (threaded_data_provider)
+    threaded_data_provider->Stop();
+}
 
 void ResourceDispatcher::DispatchMessage(const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(ResourceDispatcher, message)