Surface synchronization: Simplify Auto-Resize

It doesn't seem like there's any reason to defer auto-resize embeddings
anymore. There was a concern way back when about re-entrancy and flicker:

https://codereview.chromium.org/9702068

Child allocated LocalSurfaceIds address both of these issues.

Change-Id: Ieaefdf517f7c6c14d0e6a8ac496e233798185dc0
Reviewed-on: https://chromium-review.googlesource.com/1036501Reviewed-by: Saman Sami <samans@chromium.org>
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555149}

content/browser/renderer_host/render_widget_host_impl.cc

@@ -2182,15 +2182,14 @@ void RenderWidgetHostImpl::OnResizeOrRepaintACK(
 
   DidCompleteResizeOrRepaint(params, paint_start);
 
-  last_auto_resize_surface_id_ = params.child_allocated_local_surface_id;
-
-  if (auto_resize_enabled_) {
-    bool post_callback = new_auto_size_.IsEmpty();
-    new_auto_size_ = params.view_size;
-    if (post_callback) {
-      base::ThreadTaskRunnerHandle::Get()->PostTask(
-          FROM_HERE, base::BindOnce(&RenderWidgetHostImpl::DelayedAutoResized,
-                                    weak_factory_.GetWeakPtr()));
+  if (auto_resize_enabled_ && view_) {
+    viz::ScopedSurfaceIdAllocator scoped_allocator =
+        view_->ResizeDueToAutoResize(params.view_size,
+                                     *params.child_allocated_local_surface_id);
+
+    if (delegate_) {
+      delegate_->ResizeDueToAutoResize(
+          this, params.view_size, *params.child_allocated_local_surface_id);
     }
   }
 
@@ -2632,27 +2631,6 @@ void RenderWidgetHostImpl::GotResponseToKeyboardLockRequest(bool allowed) {
     UnlockKeyboard();
 }
 
-void RenderWidgetHostImpl::DelayedAutoResized() {
-  gfx::Size new_size = new_auto_size_;
-  // Clear the new_auto_size_ since the empty value is used as a flag to
-  // indicate that no callback is in progress (i.e. without this line
-  // DelayedAutoResized will not get called again).
-  new_auto_size_.SetSize(0, 0);
-  if (!auto_resize_enabled_)
-    return;
-
-  if (view_) {
-    viz::ScopedSurfaceIdAllocator scoped_allocator =
-        view_->ResizeDueToAutoResize(new_size,
-                                     last_auto_resize_surface_id_.value());
-
-    if (delegate_) {
-      delegate_->ResizeDueToAutoResize(this, new_size,
-                                       last_auto_resize_surface_id_.value());
-    }
-  }
-}
-
 void RenderWidgetHostImpl::DetachDelegate() {
   delegate_ = nullptr;
   latency_tracker_.reset_delegate();

content/browser/renderer_host/render_widget_host_impl.h

@@ -838,10 +838,6 @@ class CONTENT_EXPORT RenderWidgetHostImpl
   void DispatchInputEventWithLatencyInfo(const blink::WebInputEvent& event,
                                          ui::LatencyInfo* latency);
 
-  // Called when there is a new auto resize (using a post to avoid a stack
-  // which may get in recursive loops).
-  void DelayedAutoResized();
-
   void WindowSnapshotReachedScreen(int snapshot_id);
 
   void OnSnapshotFromSurfaceReceived(int snapshot_id,
@@ -938,9 +934,6 @@ class CONTENT_EXPORT RenderWidgetHostImpl
   // Visual properties that were most recently sent to the renderer.
   std::unique_ptr<VisualProperties> old_visual_properties_;
 
-  // The next auto resize to send.
-  gfx::Size new_auto_size_;
-
   // True if the render widget host should track the render widget's size as
   // opposed to visa versa.
   bool auto_resize_enabled_;
@@ -951,8 +944,6 @@ class CONTENT_EXPORT RenderWidgetHostImpl
   // The maximum size for the render widget if auto-resize is enabled.
   gfx::Size max_size_for_auto_resize_;
 
-  base::Optional<viz::LocalSurfaceId> last_auto_resize_surface_id_;
-
   bool waiting_for_screen_rects_ack_;
   gfx::Rect last_view_screen_rect_;
   gfx::Rect last_window_screen_rect_;