viz/mac: Add autoresize functionality

Add a mechanism for allowing an autoresize frame to resize the
renderer's surface.

When in auto-resize, make BrowserCompositorMac not update its size
based on the NSView size.

Bug: 805774
Change-Id: Ibc0b8b14ec7c1f4bdef30ac815d759f5894ab315
Reviewed-on: https://chromium-review.googlesource.com/892288
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533183}

content/browser/renderer_host/browser_compositor_view_mac.h

@@ -63,12 +63,20 @@ class CONTENT_EXPORT BrowserCompositorMac : public DelegatedFrameHostClient {
   void OnDidNotProduceFrame(const viz::BeginFrameAck& ack);
   void SetBackgroundColor(SkColor background_color);
   void SetDisplayColorSpace(const gfx::ColorSpace& color_space);
-  void OnNSViewWasResized();
   void UpdateVSyncParameters(const base::TimeTicks& timebase,
                              const base::TimeDelta& interval);
   void SetNeedsBeginFrames(bool needs_begin_frames);
   void SetWantsAnimateOnlyBeginFrames();
 
+  // Update the renderer's SurfaceId to reflect the current dimensions of the
+  // NSView. This will allocate a new SurfaceId if the dimensions have indeed
+  // changed.
+  void OnNSViewWasResized();
+
+  // Update the renderer's SurfaceId to reflect |size_dip| in anticipation of
+  // the NSView resizing during auto-resize.
+  void OnNSViewWillAutoResize(const gfx::Size& size_dip);
+
   // This is used to ensure that the ui::Compositor be attached to the
   // DelegatedFrameHost while the RWHImpl is visible.
   // Note: This should be called before the RWHImpl is made visible and after
@@ -187,7 +195,9 @@ class CONTENT_EXPORT BrowserCompositorMac : public DelegatedFrameHostClient {
       nullptr;
 
   // The surface for the delegated frame host, rendered into by the renderer
-  // process. Updated by OnNSViewWasResized.
+  // process.
+  void UpdateDelegatedFrameHostSurface(const gfx::Size& size_dip,
+                                       float scale_factor);
   viz::LocalSurfaceId delegated_frame_host_surface_id_;
   gfx::Size delegated_frame_host_size_pixels_;
   gfx::Size delegated_frame_host_size_dip_;

content/browser/renderer_host/browser_compositor_view_mac.mm

@@ -323,19 +323,27 @@ void BrowserCompositorMac::SetDisplayColorSpace(
 }
 
 void BrowserCompositorMac::OnNSViewWasResized() {
-  // Update the parameters we will send to the renderer via the
-  // DelgatedFrameHost.
-  gfx::Size dip_size;
+  gfx::Size size_dip;
   float scale_factor = 1.f;
-  GetViewProperties(&dip_size, &scale_factor, nullptr);
-  if (dip_size == delegated_frame_host_size_dip_ &&
+  GetViewProperties(&size_dip, &scale_factor, nullptr);
+  UpdateDelegatedFrameHostSurface(size_dip, scale_factor);
+}
+
+void BrowserCompositorMac::OnNSViewWillAutoResize(const gfx::Size& size_dip) {
+  UpdateDelegatedFrameHostSurface(size_dip, delegated_frame_host_scale_factor_);
+}
+
+void BrowserCompositorMac::UpdateDelegatedFrameHostSurface(
+    const gfx::Size& size_dip,
+    float scale_factor) {
+  if (size_dip == delegated_frame_host_size_dip_ &&
       scale_factor == delegated_frame_host_scale_factor_) {
     return;
   }
 
   delegated_frame_host_surface_id_ =
       parent_local_surface_id_allocator_.GenerateId();
-  delegated_frame_host_size_dip_ = dip_size;
+  delegated_frame_host_size_dip_ = size_dip;
   delegated_frame_host_size_pixels_ = gfx::ConvertSizeToPixel(
       delegated_frame_host_scale_factor_, delegated_frame_host_size_dip_);
   delegated_frame_host_scale_factor_ = scale_factor;

content/browser/renderer_host/render_widget_host_view_mac.h

@@ -343,6 +343,8 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   bool ShouldContinueToPauseForFrame() override;
   gfx::Rect GetBoundsInRootWindow() override;
   void OnSynchronizedDisplayPropertiesChanged() override;
+  void ResizeDueToAutoResize(const gfx::Size& new_size,
+                             uint64_t sequence_number) override;
   void DidNavigate() override;
 
   bool LockMouse() override;

content/browser/renderer_host/render_widget_host_view_mac.mm

@@ -1092,6 +1092,12 @@ void RenderWidgetHostViewMac::OnSynchronizedDisplayPropertiesChanged() {
   browser_compositor_->OnNSViewWasResized();
 }
 
+void RenderWidgetHostViewMac::ResizeDueToAutoResize(const gfx::Size& new_size,
+                                                    uint64_t sequence_number) {
+  browser_compositor_->OnNSViewWillAutoResize(new_size);
+  RenderWidgetHostViewBase::ResizeDueToAutoResize(new_size, sequence_number);
+}
+
 void RenderWidgetHostViewMac::DidNavigate() {
   browser_compositor_->DidNavigate();
 }
@@ -2838,6 +2844,11 @@ Class GetRenderWidgetHostViewCocoaClassForTesting() {
   if (!renderWidgetHostView_->render_widget_host_)
     return;
 
+  // During auto-resize it is the responsibility of the caller to ensure that
+  // the NSView and RenderWidgetHostImpl are kept in sync.
+  if (renderWidgetHostView_->render_widget_host_->auto_resize_enabled())
+    return;
+
   if (renderWidgetHostView_->render_widget_host_->delegate())
     renderWidgetHostView_->render_widget_host_->delegate()->SendScreenRects();
   else