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content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 402df2f8184557c5c114e6dd8116884b340910dc..7f1c16773ceebd3f3e19ef42a4e479e8ab70591d 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -70,6 +70,7 @@
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/display.h"
+#include "ui/gfx/frame_time.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
@@ -851,12 +852,13 @@ void RenderWidgetHostViewMac::SendVSyncParametersToRenderer() {
   if (!render_widget_host_ || !display_link_)
     return;
 
-  base::TimeTicks timebase;
-  base::TimeDelta interval;
-  if (!display_link_->GetVSyncParameters(&timebase, &interval))
+  if (!display_link_->GetVSyncParameters(&vsync_timebase_, &vsync_interval_)) {
+    vsync_timebase_ = base::TimeTicks();
+    vsync_interval_ = base::TimeDelta();
     return;
+  }
 
-  render_widget_host_->UpdateVSyncParameters(timebase, interval);
+  render_widget_host_->UpdateVSyncParameters(vsync_timebase_, vsync_interval_);
 }
 
 void RenderWidgetHostViewMac::UpdateBackingStoreScaleFactor() {
@@ -1410,6 +1412,7 @@ void RenderWidgetHostViewMac::PluginImeCompositionCompleted(
 
 void RenderWidgetHostViewMac::CompositorSwapBuffers(
     IOSurfaceID surface_handle,
+    const gfx::Rect& damage_rect,
     const gfx::Size& size,
     float surface_scale_factor,
     const std::vector<ui::LatencyInfo>& latency_info) {
@@ -1468,11 +1471,20 @@ void RenderWidgetHostViewMac::CompositorSwapBuffers(
   // current context afterward.
   bool frame_was_captured = false;
   if (frame_subscriber_) {
-    const base::TimeTicks present_time = base::TimeTicks::Now();
+    const base::TimeTicks now = gfx::FrameTime::Now();
+    base::TimeTicks present_time;
+    if (vsync_timebase_.is_null() || vsync_interval_ <= base::TimeDelta()) {
+      present_time = now;
+    } else {
+      const int64 intervals_elapsed = (now - vsync_timebase_) / vsync_interval_;
+      present_time = vsync_timebase_ +
+          (intervals_elapsed + 1) * vsync_interval_;
+    }
+
     scoped_refptr<media::VideoFrame> frame;
     RenderWidgetHostViewFrameSubscriber::DeliverFrameCallback callback;
-    if (frame_subscriber_->ShouldCaptureFrame(present_time,
-                                              &frame, &callback)) {
+    if (frame_subscriber_->ShouldCaptureFrame(
+            damage_rect, present_time, &frame, &callback)) {
       // Flush the context that updated the IOSurface, to ensure that the
       // context that does the copy picks up the correct version.
       {
@@ -1728,6 +1740,7 @@ void RenderWidgetHostViewMac::AcceleratedSurfaceBuffersSwapped(
           params.surface_handle);
 
       CompositorSwapBuffers(io_surface_id,
+                            gfx::Rect(),

[ccameron, 2014/07/25 17:21:52]

I think that this should be from params.size ... but this is dead code (only
works with --disable-delegated-rendering, which will probably be deleted soon).

[miu, 2014/07/25 18:00:13]

tl;dr: I fell back on passing an empty Rect since that's the indicator for
"damage rect unknown."

Looks like params.size is the "backbuffer size" (i.e., the surface size?)
instead of the damage size.  Do correct me here if I've got that wrong. 
Unfortunately, the params struct here doesn't seem to have the needed
information (it's different than the one used on line 1790).

                             params.size,
                             params.scale_factor,
                             params.latency_info);
@@ -1772,10 +1785,12 @@ void RenderWidgetHostViewMac::AcceleratedSurfacePostSubBuffer(
                     gpu_host_id,
                     compositing_iosurface_ ?
                         compositing_iosurface_->GetRendererID() : 0);
-  CompositorSwapBuffers(IOSurfaceIDFromSurfaceHandle(params.surface_handle),
-                        params.surface_size,
-                        params.surface_scale_factor,
-                        params.latency_info);
+  CompositorSwapBuffers(
+      IOSurfaceIDFromSurfaceHandle(params.surface_handle),
+      gfx::Rect(params.x, params.y, params.width, params.height),
+      params.surface_size,
+      params.surface_scale_factor,
+      params.latency_info);
 }
 
 void RenderWidgetHostViewMac::AcceleratedSurfaceSuspend() {