Delay UpdateRect until the SwapBuffers callback when accelerated compositing is on.

content/browser/renderer_host/render_widget_host.cc

 // Copyright (c) 2011 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/browser/renderer_host/render_widget_host.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 177 matching lines @@
   bool handled = true;
   bool msg_is_ok = true;
   IPC_BEGIN_MESSAGE_MAP_EX(RenderWidgetHost, msg, msg_is_ok)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RenderViewReady, OnMsgRenderViewReady)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RenderViewGone, OnMsgRenderViewGone)
     IPC_MESSAGE_HANDLER(ViewHostMsg_Close, OnMsgClose)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RequestMove, OnMsgRequestMove)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetTooltipText, OnMsgSetTooltipText)
     IPC_MESSAGE_HANDLER(ViewHostMsg_PaintAtSize_ACK, OnMsgPaintAtSizeAck)
     IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateRect, OnMsgUpdateRect)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateIsDelayed, OnMsgUpdateIsDelayed)
     IPC_MESSAGE_HANDLER(ViewHostMsg_HandleInputEvent_ACK, OnMsgInputEventAck)
     IPC_MESSAGE_HANDLER(ViewHostMsg_Focus, OnMsgFocus)
     IPC_MESSAGE_HANDLER(ViewHostMsg_Blur, OnMsgBlur)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetCursor, OnMsgSetCursor)
     IPC_MESSAGE_HANDLER(ViewHostMsg_TextInputStateChanged,
                         OnMsgTextInputStateChanged)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ImeCompositionRangeChanged,
                         OnMsgImeCompositionRangeChanged)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ImeCancelComposition,
                         OnMsgImeCancelComposition)
@@ skipping 821 matching lines @@
     DidUpdateBackingStore(params, paint_start);
   }
 
   // Log the time delta for processing a paint message. On platforms that don't
   // support asynchronous painting, this is equivalent to
   // MPArch.RWH_TotalPaintTime.
   TimeDelta delta = TimeTicks::Now() - paint_start;
   UMA_HISTOGRAM_TIMES("MPArch.RWH_OnMsgUpdateRect", delta);
 }
 
+void RenderWidgetHost::OnMsgUpdateIsDelayed() {
+  // Nothing to do, this message was just to unblock the UI thread.
+}
+
 void RenderWidgetHost::DidUpdateBackingStore(
     const ViewHostMsg_UpdateRect_Params& params,
     const TimeTicks& paint_start) {
   TRACE_EVENT0("renderer_host", "RenderWidgetHost::DidUpdateBackingStore");
   TimeTicks update_start = TimeTicks::Now();
 
-  // ACK early so we can prefetch the next PaintRect if there is a next one.
-  // This must be done AFTER we're done painting with the bitmap supplied by the
-  // renderer. This ACK is a signal to the renderer that the backing store can
-  // be re-used, so the bitmap may be invalid after this call.
-  Send(new ViewMsg_UpdateRect_ACK(routing_id_));
+  if (ViewHostMsg_UpdateRect_Flags::needs_ack(params.flags)) {
+      // ACK early so we can prefetch the next PaintRect if there is a next one.

[darin (slow to review), 2011/11/15 08:06:04]

nit: indentation

[piman, 2011/11/16 01:00:55]

Done.

+      // This must be done AFTER we're done painting with the bitmap supplied by
+      // the renderer. This ACK is a signal to the renderer that the backing
+      // store can be re-used, so the bitmap may be invalid after this call.
+      Send(new ViewMsg_UpdateRect_ACK(routing_id_));
+  }
 
   // Move the plugins if the view hasn't already been destroyed.  Plugin moves
   // will not be re-issued, so must move them now, regardless of whether we
   // paint or not.  MovePluginWindows attempts to move the plugin windows and
   // in the process could dispatch other window messages which could cause the
   // view to be destroyed.
   if (view_)
     view_->MovePluginWindows(params.plugin_window_moves);
 
   // We don't need to update the view if the view is hidden. We must do this
@@ skipping 402 matching lines @@
     pending_mouse_lock_request_ = false;
     if (!view_ || !view_->HasFocus()|| !view_->LockMouse()) {
       Send(new ViewMsg_LockMouse_ACK(routing_id_, false));
       return false;
     } else {
       Send(new ViewMsg_LockMouse_ACK(routing_id_, true));
       return true;
     }
   }
 }