Drop frontbuffers with ui-use-gpu-process, synchronized with browser, decoupled from backbuffer dro…

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 bf1dc08e7233dd8e6a8b05d00217182b95585585..5452747954ca81d141c8ac1d60756c44aa0d8e25 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -9,7 +9,6 @@
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
-#include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
 #include "content/browser/renderer_host/backing_store_skia.h"
@@ -134,6 +133,13 @@ bool ShouldSendPinchGesture() {
   return pinch_allowed;
 }
 
+bool ShouldReleaseFrontSurface() {
+  static bool release_front_surface_allowed =
+      CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableUIReleaseFrontSurface);
+  return release_front_surface_allowed;
+}
+
 }  // namespace
 
 // We have to implement the WindowObserver interface on a separate object
@@ -215,6 +221,11 @@ RenderWidgetHostViewAura::RenderWidgetHostViewAura(RenderWidgetHost* host)
       can_compose_inline_(true),
       has_composition_text_(false),
       current_surface_(0),
+      current_surface_is_protected_(true),
+      current_surface_in_use_by_compositor_(true),
+      pending_thumbnail_tasks_(0),
+      protection_state_id_(0),
+      surface_route_id_(0),
       paint_canvas_(NULL),
       synthetic_move_sent_(false),
       needs_update_texture_(false) {
@@ -291,15 +302,32 @@ RenderWidgetHost* RenderWidgetHostViewAura::GetRenderWidgetHost() const {
 }
 
 void RenderWidgetHostViewAura::DidBecomeSelected() {
+  if (host_->IsVisible())
+    return;
+
   host_->WasRestored();
+
   if (!current_surface_ && host_->is_accelerated_compositing_active() &&
       !released_front_lock_.get())
     released_front_lock_ = window_->GetRootWindow()->GetCompositorLock();
+
+  AdjustSurfaceProtection();
 }
 
 void RenderWidgetHostViewAura::WasHidden() {
+  if (!host_->IsVisible())
+    return;
+
   host_->WasHidden();
+
   released_front_lock_ = NULL;
+
+  if (ShouldReleaseFrontSurface()) {
+    current_surface_ = 0;
+    UpdateExternalTexture();
+  }
+
+  AdjustSurfaceProtection();
 }
 
 void RenderWidgetHostViewAura::SetSize(const gfx::Size& size) {
@@ -493,11 +521,25 @@ void RenderWidgetHostViewAura::CopyFromCompositingSurface(
   unsigned char* addr = static_cast<unsigned char*>(
       output->getTopDevice()->accessBitmap(true).getPixels());
   scoped_callback_runner.Release();
+  // Wrap the callback with an internal handler so that we can inject our
+  // own completion handlers (where we can call AdjustSurfaceProtection).
+  base::Callback<void(bool)> wrapper_callback = base::Bind(
+      &RenderWidgetHostViewAura::CopyFromCompositingSurfaceFinished,
+      AsWeakPtr(),
+      callback);
+  ++pending_thumbnail_tasks_;

[sky, 2012/06/13 16:21:23]

Why does this need to be delayed, and why do you need to schedule more than one
at a time?

[mmocny, 2012/06/13 18:40:05]

The browser thumbnailer will call this multiple times if we switch tabs during
the duration of the previous async read.  Discussing with @mazda, the browser
thumbnailer is written to ignore all but the last read in such a case, so I
cannot ignore new requests nor cancel current ones, so I hdd to schedule
multiple concurrently.

If we want to fix the browser thumbnailer to not issue multiple concurrent
reads, then we can fix this, but I suspect that should be a follow on.

On 2012/06/13 16:21:23, sky wrote:

   gl_helper->CopyTextureTo(container->texture_id(),
                            container->size(),
                            size_in_pixel,
                            addr,
-                           callback);
+                           wrapper_callback);
+}
+
+void RenderWidgetHostViewAura::CopyFromCompositingSurfaceFinished(

[sky, 2012/06/13 16:21:23]

Position should match that of header.

[mmocny, 2012/06/13 18:40:05]

Done.

+    base::Callback<void(bool)> callback, bool result) {
+  --pending_thumbnail_tasks_;
+  AdjustSurfaceProtection();
+  callback.Run(result);
 }
 
 void RenderWidgetHostViewAura::OnAcceleratedCompositingStateChange() {
@@ -514,14 +556,14 @@ void RenderWidgetHostViewAura::UpdateExternalTexture() {
   needs_update_texture_ = false;
   if (current_surface_ != 0 &&
       host_->is_accelerated_compositing_active()) {
-
+    DCHECK(image_transport_clients_.find(current_surface_) !=

[sky, 2012/06/13 16:21:23]

DCHECK_NE

[mmocny, 2012/06/13 18:40:05]

DCHECK_NE seems to cause compile failure when values are std::map iterator.  (no
match for 'operator<<').
grepped the code base and could not find another use of DCHECK_NE with iterator
values.

On 2012/06/13 16:21:23, sky wrote:

+           image_transport_clients_.end());
     ImageTransportClient* container =
         image_transport_clients_[current_surface_];
     if (container)
       container->Update();
     window_->SetExternalTexture(container);
-
-    released_front_lock_ = NULL;
+    current_surface_in_use_by_compositor_ = true;
 
     if (!container) {
       resize_locks_.clear();
@@ -558,6 +600,18 @@ void RenderWidgetHostViewAura::UpdateExternalTexture() {
     }
   } else {
     window_->SetExternalTexture(NULL);
+    ui::Compositor* compositor = GetCompositor();
+    if (!compositor->DrawPending()) {
+      current_surface_in_use_by_compositor_ = false;
+      AdjustSurfaceProtection();
+    } else {
+      on_compositing_ended_callbacks_.push_back(
+          base::Bind(&RenderWidgetHostViewAura::
+                         SetSurfaceNotInUseByCompositor,
+                     AsWeakPtr()));
+      if (!compositor->HasObserver(this))
+        compositor->AddObserver(this);
+    }
     resize_locks_.clear();
   }
 }
@@ -565,36 +619,63 @@ void RenderWidgetHostViewAura::UpdateExternalTexture() {
 void RenderWidgetHostViewAura::AcceleratedSurfaceBuffersSwapped(
     const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params_in_pixel,
     int gpu_host_id) {
+  // If protection state changed, then this swap is stale. We must still ACK but
+  // do not update current_surface_ since it may have been discarded.
+  if (params_in_pixel.protection_state_id &&
+      params_in_pixel.protection_state_id != protection_state_id_) {
+    DCHECK(!current_surface_);
+    if (params_in_pixel.require_ack) {
+      RenderWidgetHostImpl::AcknowledgeSwapBuffers(
+          params_in_pixel.route_id, gpu_host_id);
+    }
+    return;
+  }
   current_surface_ = params_in_pixel.surface_handle;
+  // If we don't require an ACK that means the content is not a fresh updated
+  // new frame, rather we are just resetting our handle to some old content that
+  // we still hadn't discarded. Although we could display immediately, by not
+  // resetting the compositor lock here, we give us some time to get a fresh
+  // frame which means fewer content flashes.
+  if (params_in_pixel.require_ack)
+    released_front_lock_ = NULL;
+
+  DCHECK(current_surface_);
   UpdateExternalTexture();
 
   ui::Compositor* compositor = GetCompositor();
   if (!compositor) {
     // We have no compositor, so we have no way to display the surface.
     // Must still send the ACK.
-    RenderWidgetHostImpl::AcknowledgeSwapBuffers(params_in_pixel.route_id,
-        gpu_host_id);
+    if (params_in_pixel.require_ack) {
+      RenderWidgetHostImpl::AcknowledgeSwapBuffers(params_in_pixel.route_id,
+          gpu_host_id);
+    }
   } else {
+    DCHECK(image_transport_clients_.find(params_in_pixel.surface_handle) !=
+           image_transport_clients_.end());
     gfx::Size surface_size_in_pixel =
         image_transport_clients_[params_in_pixel.surface_handle]->size();
     gfx::Size surface_size = content::ConvertSizeToDIP(this,
                                                        surface_size_in_pixel);
     window_->SchedulePaintInRect(gfx::Rect(surface_size));
 
-    if (!resize_locks_.empty() && !compositor->DrawPending()) {
-      // If we are waiting for the resize, fast-track the ACK.
-      // However only do so if we're not between the Draw() and the
-      // OnCompositingEnded(), because out-of-order execution in the GPU process
-      // might corrupt the "front buffer" for the currently issued frame.
-      RenderWidgetHostImpl::AcknowledgeSwapBuffers(
-          params_in_pixel.route_id, gpu_host_id);
-    } else {
-      // Add sending an ACK to the list of things to do OnCompositingEnded
-      on_compositing_ended_callbacks_.push_back(
-          base::Bind(&RenderWidgetHostImpl::AcknowledgeSwapBuffers,
-                     params_in_pixel.route_id, gpu_host_id));
-      if (!compositor->HasObserver(this))
-        compositor->AddObserver(this);
+    if (params_in_pixel.require_ack) {
+      if (!resize_locks_.empty() && !compositor->DrawPending()) {
+        // If we are waiting for the resize, fast-track the ACK.
+        // However only do so if we're not between the Draw() and the
+        // OnCompositingEnded(), because out-of-order execution in the GPU
+        // process might corrupt the "front buffer" for the currently issued
+        // frame.
+        RenderWidgetHostImpl::AcknowledgeSwapBuffers(
+            params_in_pixel.route_id, gpu_host_id);
+      } else {
+        // Add sending an ACK to the list of things to do OnCompositingEnded
+        on_compositing_ended_callbacks_.push_back(
+            base::Bind(&RenderWidgetHostImpl::AcknowledgeSwapBuffers,
+                       params_in_pixel.route_id, gpu_host_id));
+        if (!compositor->HasObserver(this))
+          compositor->AddObserver(this);
+      }
     }
   }
 }
@@ -602,7 +683,18 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceBuffersSwapped(
 void RenderWidgetHostViewAura::AcceleratedSurfacePostSubBuffer(
     const GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params& params_in_pixel,
     int gpu_host_id) {
+  // If visible state changed, then this PSB is stale. We must still ACK but
+  // do not update current_surface_.
+  if (params_in_pixel.protection_state_id &&
+      params_in_pixel.protection_state_id != protection_state_id_) {
+    DCHECK(!current_surface_);
+    RenderWidgetHostImpl::AcknowledgePostSubBuffer(params_in_pixel.route_id,
+        gpu_host_id);
+    return;
+  }
   current_surface_ = params_in_pixel.surface_handle;
+  released_front_lock_ = NULL;
+  DCHECK(current_surface_);
   UpdateExternalTexture();
 
   ui::Compositor* compositor = GetCompositor();
@@ -612,6 +704,8 @@ void RenderWidgetHostViewAura::AcceleratedSurfacePostSubBuffer(
     RenderWidgetHostImpl::AcknowledgePostSubBuffer(
         params_in_pixel.route_id, gpu_host_id);
   } else {
+    DCHECK(image_transport_clients_.find(params_in_pixel.surface_handle) !=
+           image_transport_clients_.end());
     gfx::Size surface_size_in_pixel =
         image_transport_clients_[params_in_pixel.surface_handle]->size();
 
@@ -658,7 +752,8 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceNew(
       int32 width_in_pixel,
       int32 height_in_pixel,
       uint64* surface_handle,
-      TransportDIB::Handle* shm_handle) {
+      TransportDIB::Handle* shm_handle,
+      int32 route_id) {
   ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
   scoped_refptr<ImageTransportClient> surface(factory->CreateTransportClient(
         gfx::Size(width_in_pixel, height_in_pixel), surface_handle));
@@ -669,10 +764,14 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceNew(
   *shm_handle = surface->Handle();
 
   image_transport_clients_[*surface_handle] = surface;
+
+  surface_route_id_ = route_id;
 }
 
 void RenderWidgetHostViewAura::AcceleratedSurfaceRelease(
     uint64 surface_handle) {
+  DCHECK(image_transport_clients_.find(surface_handle) !=
+         image_transport_clients_.end());
   if (current_surface_ == surface_handle) {
     current_surface_ = 0;
     UpdateExternalTexture();
@@ -680,6 +779,38 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceRelease(
   image_transport_clients_.erase(surface_handle);
 }
 
+void RenderWidgetHostViewAura::SetSurfaceNotInUseByCompositor() {
+  if (current_surface_ || host_->IsVisible())
+    return;
+  current_surface_in_use_by_compositor_ = false;
+  AdjustSurfaceProtection();
+}
+
+void RenderWidgetHostViewAura::AdjustSurfaceProtection() {
+  // If the current surface is non null, it is protected.
+  // If we are visible, it is protected.
+  // If we are not visible and current surface is null, still stay protected
+  // until we finish thumbnailing and compositing.
+  bool surface_is_protected =
+      current_surface_ ||
+      host_->IsVisible() ||
+      (current_surface_is_protected_ &&
+          (pending_thumbnail_tasks_ || current_surface_in_use_by_compositor_));
+  if (current_surface_is_protected_ == surface_is_protected)
+    return;
+  current_surface_is_protected_ = surface_is_protected;
+  ++protection_state_id_;
+
+  if (!surface_route_id_ || !shared_surface_handle_.parent_gpu_process_id)
+    return;
+
+  RenderWidgetHostImpl::SendFrontSurfaceIsProtected(
+      surface_is_protected,
+      protection_state_id_,
+      surface_route_id_,
+      shared_surface_handle_.parent_gpu_process_id);
+}
+
 void RenderWidgetHostViewAura::SetBackground(const SkBitmap& background) {
   content::RenderWidgetHostViewBase::SetBackground(background);
   host_->SetBackground(background);
@@ -1218,6 +1349,10 @@ void RenderWidgetHostViewAura::OnCompositingAborted(
 void RenderWidgetHostViewAura::OnLostResources(ui::Compositor* compositor) {
   image_transport_clients_.clear();
   current_surface_ = 0;
+  protection_state_id_ = 0;
+  current_surface_is_protected_ = true;
+  current_surface_in_use_by_compositor_ = true;
+  surface_route_id_ = 0;
   UpdateExternalTexture();
   locks_pending_draw_.clear();