Simplify mailbox handling for browser plugin

content/renderer/browser_plugin/browser_plugin_compositing_helper.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/browser_plugin/browser_plugin_compositing_helper.h"
 
 #include "cc/layers/delegated_renderer_layer.h"
 #include "cc/layers/solid_color_layer.h"
 #include "cc/layers/texture_layer.h"
 #include "cc/output/context_provider.h"
@@ skipping 66 matching lines @@
     buffer_size_ = new_size;
     // The container size is in DIP, so is the layer size.
     // Buffer size is in physical pixels, so we need to adjust
     // it by the device scale factor.
     gfx::Size device_scale_adjusted_size = gfx::ToFlooredSize(
         gfx::ScaleSize(buffer_size_, 1.0f / device_scale_factor));
     layer->SetBounds(device_scale_adjusted_size);
   }
 }
 
-// If we have a mailbox that was freed up from the compositor,
-// but we are not expected to return it to the guest renderer
-// via an ACK, we should free it because we now own it.
-// To free the mailbox memory, we need a context to consume it
-// into a texture ID and then delete this texture ID.
-// We use a shared graphics context accessible from the main
-// thread to do it.
-void BrowserPluginCompositingHelper::FreeMailboxMemory(
-    const std::string& mailbox_name,
-    unsigned sync_point) {
-  if (mailbox_name.empty())
-    return;
-
-  scoped_refptr<cc::ContextProvider> context_provider =
-      RenderThreadImpl::current()->OffscreenContextProviderForMainThread();
-  if (!context_provider.get())
-    return;
-
-  WebKit::WebGraphicsContext3D *context = context_provider->Context3d();
-  // When a buffer is released from the compositor, we also get a
-  // sync point that specifies when in the command buffer
-  // it's safe to use it again.
-  // If the sync point is non-zero, we need to tell our context
-  // to wait until this sync point is reached before we can safely
-  // delete the buffer.
-  if (sync_point)
-    context->waitSyncPoint(sync_point);
-
-  unsigned texture_id = context->createTexture();
-  context->bindTexture(GL_TEXTURE_2D, texture_id);
-  context->consumeTextureCHROMIUM(
-      GL_TEXTURE_2D,
-      reinterpret_cast<const int8*>(mailbox_name.data()));
-  context->deleteTexture(texture_id);
-}
-
 void BrowserPluginCompositingHelper::MailboxReleased(
     const std::string& mailbox_name,
     int gpu_route_id,
     int gpu_host_id,
     unsigned sync_point,
     bool lost_resource) {
   if (lost_resource) {
     // Recurse with an empty mailbox if the one being released was lost.
     MailboxReleased(std::string(), gpu_route_id, gpu_host_id, 0, false);
     return;
   }
 
   // This means the GPU process crashed and we have nothing further to do.
   // Nobody is expecting an ACK and the buffer doesn't need to be deleted
   // because it went away with the GPU process.
   if (last_host_id_ != gpu_host_id)
     return;
 
   // This means the guest crashed.
   // Either ACK the last buffer, so texture transport could
   // be destroyed of delete the mailbox if nobody wants it back.
   if (last_route_id_ != gpu_route_id) {
-    if (!ack_pending_for_crashed_guest_) {
-      FreeMailboxMemory(mailbox_name, sync_point);
-    } else {
+    if (ack_pending_for_crashed_guest_) {
       ack_pending_for_crashed_guest_ = false;
       browser_plugin_manager_->Send(
           new BrowserPluginHostMsg_BuffersSwappedACK(
               host_routing_id_,
               instance_id_,
               gpu_route_id,
               gpu_host_id,
               mailbox_name,
               sync_point));
     }
     return;
   }
 
   // We need to send an ACK to TextureImageTransportSurface
   // for every buffer it sends us. However, if a buffer is freed up from
   // the compositor in cases like switching back to SW mode without a new
   // buffer arriving, no ACK is needed and we destroy this buffer.
   if (!ack_pending_) {
-    FreeMailboxMemory(mailbox_name, sync_point);
     last_mailbox_valid_ = false;
     return;
   }
   ack_pending_ = false;
   browser_plugin_manager_->Send(
       new BrowserPluginHostMsg_BuffersSwappedACK(
           host_routing_id_,
           instance_id_,
           gpu_route_id,
           gpu_host_id,
@@ skipping 114 matching lines @@
 }
 
 void BrowserPluginCompositingHelper::UpdateVisibility(bool visible) {
   if (texture_layer_.get())
     texture_layer_->SetIsDrawable(visible);
   if (delegated_layer_.get())
     delegated_layer_->SetIsDrawable(visible);
 }
 
 }  // namespace content