Added FrameFuture class

android_webview/browser/browser_view_renderer.cc

Index: android_webview/browser/browser_view_renderer.cc
diff --git a/android_webview/browser/browser_view_renderer.cc b/android_webview/browser/browser_view_renderer.cc
index ba3defa6fa867c16a79348e24e3f270ea2f22f0a..28841cda09e6511df15d44e15afb2c28095faffc 100644
--- a/android_webview/browser/browser_view_renderer.cc
+++ b/android_webview/browser/browser_view_renderer.cc
@@ -232,43 +232,42 @@ bool BrowserViewRenderer::OnDrawHardware() {
   gfx::Rect viewport_rect_for_tile_priority =
       ComputeViewportRectForTilePriority();
 
+  scoped_refptr<content::SynchronousCompositor::FrameFuture> frame_future;
+
   if (async_on_draw_hardware_) {
-    compositor_->DemandDrawHwAsync(size_, viewport_rect_for_tile_priority,
-                                   transform_for_tile_priority);
+    frame_future = compositor_->DemandDrawHwAsync(
+        size_, viewport_rect_for_tile_priority, transform_for_tile_priority);
     return current_compositor_frame_consumer_->HasFrameOnUI();
+  } else {
+    frame_future = compositor_->DemandDrawHw(
+        size_, viewport_rect_for_tile_priority, transform_for_tile_priority);
   }
 
-  content::SynchronousCompositor::Frame frame = compositor_->DemandDrawHw(
-      size_, viewport_rect_for_tile_priority, transform_for_tile_priority);
-  if (!frame.frame) {
+  if (!(frame_future && frame_future->getFrame() &&
+        frame_future->getFrame()->frame)) {

[boliu, 2016/09/20 00:27:56]

can't call getFrame here because we will want to have getFrame pass ownership
but also can't remove this block either because of the binding init ordering
hmmmm I think the only way is to have RenderThreadManager work with both
FrameFuture and Frame, until we can ship the async path :(

     TRACE_EVENT_INSTANT0("android_webview", "NoNewFrame",
                          TRACE_EVENT_SCOPE_THREAD);
     return current_compositor_frame_consumer_->HasFrameOnUI();
   }
 
-  OnDrawHardwareProcessFrame(std::move(frame));
+  OnDrawHardwareProcessFrame(std::move(frame_future));
   return true;
 }
 
 void BrowserViewRenderer::OnDrawHardwareProcessFrame(
-    content::SynchronousCompositor::Frame frame) {
-  TRACE_EVENT0("android_webview",
-               "BrowserViewRenderer::OnDrawHardwareProcessFrame");
-  if (!frame.frame)
-    return;
-
+    scoped_refptr<content::SynchronousCompositor::FrameFuture> frame_future) {
   gfx::Transform transform_for_tile_priority =
       external_draw_constraints_.transform;
   gfx::Rect viewport_rect_for_tile_priority =
       ComputeViewportRectForTilePriority();
-  std::unique_ptr<ChildFrame> child_frame = base::MakeUnique<ChildFrame>(
-      frame.compositor_frame_sink_id, std::move(frame.frame), compositor_id_,
-      viewport_rect_for_tile_priority.IsEmpty(), transform_for_tile_priority,
-      offscreen_pre_raster_, external_draw_constraints_.is_layer);
 
   ReturnUnusedResource(
       current_compositor_frame_consumer_->PassUncommittedFrameOnUI());
-  current_compositor_frame_consumer_->SetFrameOnUI(std::move(child_frame));
+
+  current_compositor_frame_consumer_->SetFrameOnUI(base::MakeUnique<ChildFrame>(
+      std::move(frame_future), compositor_id_,
+      viewport_rect_for_tile_priority.IsEmpty(), transform_for_tile_priority,
+      offscreen_pre_raster_, external_draw_constraints_.is_layer));
 }
 
 gfx::Rect BrowserViewRenderer::ComputeViewportRectForTilePriority() {
@@ -313,17 +312,20 @@ void BrowserViewRenderer::RemoveCompositorFrameConsumer(
 
 void BrowserViewRenderer::ReturnUnusedResource(
     std::unique_ptr<ChildFrame> child_frame) {
-  if (!child_frame.get() || !child_frame->frame.get())
+  if (!child_frame.get() || !child_frame->frame_future->hasFrame())
     return;
 
   cc::ReturnedResourceArray resources;
   cc::TransferableResource::ReturnResources(
-      child_frame->frame->delegated_frame_data->resource_list, &resources);
+      child_frame->frame_future->getFrame()
+          ->frame->delegated_frame_data->resource_list,
+      &resources);
   content::SynchronousCompositor* compositor =
       FindCompositor(child_frame->compositor_id);
   if (compositor && !resources.empty())
-    compositor->ReturnResources(child_frame->compositor_frame_sink_id,
-                                resources);
+    compositor->ReturnResources(
+        child_frame->frame_future->getFrame()->compositor_frame_sink_id,
+        resources);
 }
 
 void BrowserViewRenderer::ReturnResourceFromParent(