Move the content-dependent RecreateLayer logic from aura::Window to RWHVA

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 65a5fb4aa8113b24261f45143f3f2144ffe36e2d..98275c47f9854c4e2abc56da4fb6b200da726bcd 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -119,6 +119,11 @@ class MemoryHolder : public base::RefCounted<MemoryHolder> {
 
 namespace {
 
+void MailboxReleaseCallback(scoped_ptr<base::SharedMemory> shared_memory,
+                            unsigned sync_point, bool lost_resource) {
+  // NOTE: shared_memory will get released when we go out of scope.
+}
+
 // In mouse lock mode, we need to prevent the (invisible) cursor from hitting
 // the border of the view, in order to get valid movement information. However,
 // forcing the cursor back to the center of the view after each mouse move
@@ -2491,28 +2496,51 @@ bool RenderWidgetHostViewAura::HasHitTestMask() const {
 void RenderWidgetHostViewAura::GetHitTestMask(gfx::Path* mask) const {
 }
 
-scoped_refptr<ui::Texture> RenderWidgetHostViewAura::CopyTexture() {
-  if (!host_->is_accelerated_compositing_active())
-    return scoped_refptr<ui::Texture>();
-
-  ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
-  GLHelper* gl_helper = factory->GetGLHelper();
-  if (!gl_helper)
-    return scoped_refptr<ui::Texture>();
-
-  if (!current_surface_.get())
-    return scoped_refptr<ui::Texture>();
-
-  WebKit::WebGLId texture_id =
-      gl_helper->CopyTexture(current_surface_->PrepareTexture(),
-                             current_surface_->size());
-  if (!texture_id)
-    return scoped_refptr<ui::Texture>();
-
-  return scoped_refptr<ui::Texture>(
-      factory->CreateOwnedTexture(
+void RenderWidgetHostViewAura::DidRecreateLayer(ui::Layer *old_layer,
+                                                ui::Layer *new_layer) {
+  float mailbox_scale_factor;
+  cc::TextureMailbox old_mailbox =
+      old_layer->GetTextureMailbox(&mailbox_scale_factor);
+  scoped_refptr<ui::Texture> old_texture = old_layer->external_texture();
+  // Move the original texture to the new layer if the old layer has a
+  // texture and we could copy it into the old layer,
+  // crbug.com/175211.

[danakj, 2013/09/11 17:55:05]

This bug is marked as fixed, but has no context at all to help me understand why
we're swapping the old texture into the new layer instead of giving the new
layer a copy of the old texture. Can you fill me in?

[piman, 2013/09/12 01:02:33]

Done.

+  if (old_texture.get()) {
+    ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
+    GLHelper* gl_helper = factory->GetGLHelper();
+    scoped_refptr<ui::Texture> new_texture;
+    if (host_->is_accelerated_compositing_active() &&

[danakj, 2013/09/11 17:55:05]

Can you explain how do we have old_texture.get() but not have accelerated
compositing active?

+        gl_helper && current_surface_.get()) {
+      WebKit::WebGLId texture_id =
+          gl_helper->CopyTexture(current_surface_->PrepareTexture(),
+                                 current_surface_->size());
+      if (texture_id) {
+        new_texture = factory->CreateOwnedTexture(
           current_surface_->size(),
-          current_surface_->device_scale_factor(), texture_id));
+          current_surface_->device_scale_factor(), texture_id);
+      }
+    }
+    old_layer->SetExternalTexture(new_texture);
+    new_layer->SetExternalTexture(old_texture);
+  } else if (old_mailbox.IsSharedMemory()) {
+    base::SharedMemory* old_buffer = old_mailbox.shared_memory();
+    const size_t size = old_mailbox.shared_memory_size_in_bytes();
+
+    scoped_ptr<base::SharedMemory> new_buffer(new base::SharedMemory);
+    new_buffer->CreateAndMapAnonymous(size);
+
+    if (old_buffer->memory() && new_buffer->memory()) {
+      memcpy(new_buffer->memory(), old_buffer->memory(), size);
+      base::SharedMemory* new_buffer_raw_ptr = new_buffer.get();
+      cc::TextureMailbox::ReleaseCallback callback =
+          base::Bind(MailboxReleaseCallback, Passed(&new_buffer));
+      cc::TextureMailbox new_mailbox(new_buffer_raw_ptr,
+                                     old_mailbox.shared_memory_size(),
+                                     callback);
+      new_layer->SetTextureMailbox(new_mailbox, mailbox_scale_factor);
+    }
+  }
+  // TODO(piman): handle delegated frames.
 }
 
 ////////////////////////////////////////////////////////////////////////////////