[Android] Provide synchronized input flush with BeginFrame

content/browser/renderer_host/render_widget_host_view_android.cc

 // Copyright (c) 2012 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_view_android.h"
 
 #include <android/bitmap.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 96 matching lines @@
     ContentViewCoreImpl* content_view_core)
     : host_(widget_host),
       needs_begin_frame_(false),
       are_layers_attached_(true),
       content_view_core_(NULL),
       ime_adapter_android_(this),
       cached_background_color_(SK_ColorWHITE),
       texture_id_in_layer_(0),
       current_mailbox_output_surface_id_(kUndefinedOutputSurfaceId),
       weak_ptr_factory_(this),
-      overscroll_effect_enabled_(true) {
+      overscroll_effect_enabled_(true),
+      flush_input_requested_(false) {
   if (CompositorImpl::UsesDirectGL()) {
     surface_texture_transport_.reset(new SurfaceTextureTransportClient());
     layer_ = surface_texture_transport_->Initialize();
     layer_->SetIsDrawable(true);
   } else {
     if (CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kEnableDelegatedRenderer)) {
       delegated_renderer_layer_ = cc::DelegatedRendererLayer::Create(this);
       layer_ = delegated_renderer_layer_;
     } else {
@@ skipping 325 matching lines @@
     return;
 
   cached_background_color_ = color;
   if (content_view_core_)
     content_view_core_->OnBackgroundColorChanged(color);
 }
 
 void RenderWidgetHostViewAndroid::SendBeginFrame(
     const cc::BeginFrameArgs& args) {
   TRACE_EVENT0("cc", "RenderWidgetHostViewAndroid::SendBeginFrame");
-  if (host_)
-    host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
+  if (!host_)
+    return;
+
+  if (flush_input_requested_) {
+    flush_input_requested_ = false;
+    host_->FlushInput();
+    content_view_core_->RemoveBeginFrameSubscriber();

[brianderson, 2013/09/25 22:23:14]

Is it possible that this class gets destroyed after OnSetNeedsFlushInput but
before we get here?  If so, we should probably check for that case and make sure
we balance the calls in the destructor if we need to.

We should probably do the same thing for OnSetNeedsBeginFrame's subscription as
well.

[jdduke (slow), 2013/09/25 23:31:09]

ContentViewCore will automatically reset any vsync subscribers when this is
destroyed, but you're right that it would be unbalanced otherwise.  

+  }
+
+  host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
 }
 
 void RenderWidgetHostViewAndroid::OnSetNeedsBeginFrame(
     bool enabled) {
   TRACE_EVENT1("cc", "RenderWidgetHostViewAndroid::OnSetNeedsBeginFrame",
                "enabled", enabled);
   // ContentViewCoreImpl handles multiple subscribers to the BeginFrame, so
   // we have to make sure calls to ContentViewCoreImpl's SetNeedsBeginFrame

[brianderson, 2013/09/25 22:23:14]

Comment should not refer to SetNeedsBeginFrame anymore.

[jdduke (slow), 2013/09/25 23:31:09]

Done.

   // are balanced, even if RenderWidgetHostViewAndroid's may not be.
   if (content_view_core_ && needs_begin_frame_ != enabled) {
-    content_view_core_->SetNeedsBeginFrame(enabled);
+    if (enabled)
+      content_view_core_->AddBeginFrameSubscriber();
+    else
+      content_view_core_->RemoveBeginFrameSubscriber();
     needs_begin_frame_ = enabled;
   }
 }
 
 void RenderWidgetHostViewAndroid::OnStartContentIntent(
     const GURL& content_url) {
   if (content_view_core_)
     content_view_core_->StartContentIntent(content_url);
 }
 
@@ skipping 478 matching lines @@
   if (host_) {
     SynchronousCompositorImpl* compositor =
         SynchronousCompositorImpl::FromID(host_->GetProcess()->GetID(),
                                           host_->GetRoutingID());
     if (compositor)
       return compositor->HandleInputEvent(input_event);
   }
   return INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
 }
 
+void RenderWidgetHostViewAndroid::OnSetNeedsFlushInput() {
+  if (flush_input_requested_)
+    return;
+  flush_input_requested_ = true;
+  content_view_core_->AddBeginFrameSubscriber();
+}
+
 void RenderWidgetHostViewAndroid::OnAccessibilityEvents(
     const std::vector<AccessibilityHostMsg_EventParams>& params) {
   if (!host_ ||
       host_->accessibility_mode() != AccessibilityModeComplete ||
       !content_view_core_) {
     return;
   }
 
   if (!GetBrowserAccessibilityManager()) {
     SetBrowserAccessibilityManager(
@@ skipping 327 matching lines @@
 // RenderWidgetHostView, public:
 
 // static
 RenderWidgetHostView*
 RenderWidgetHostView::CreateViewForWidget(RenderWidgetHost* widget) {
   RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
   return new RenderWidgetHostViewAndroid(rwhi, NULL);
 }
 
 } // namespace content