Hook up ui::Compositor to Display's BeginFrameSource

content/browser/compositor/browser_compositor_output_surface.cc

Index: content/browser/compositor/browser_compositor_output_surface.cc
diff --git a/content/browser/compositor/browser_compositor_output_surface.cc b/content/browser/compositor/browser_compositor_output_surface.cc
index f865702effe067a645bc434c72882385ed5195a5..0b0e21ff4d93b4291fd82094d18828126be36a01 100644
--- a/content/browser/compositor/browser_compositor_output_surface.cc
+++ b/content/browser/compositor/browser_compositor_output_surface.cc
@@ -11,6 +11,7 @@
 #include "base/location.h"
 #include "base/strings/string_number_conversions.h"
 #include "cc/base/switches.h"
+#include "cc/output/output_surface_client.h"
 #include "content/browser/compositor/browser_compositor_overlay_candidate_validator.h"
 #include "content/browser/compositor/reflector_impl.h"
 #include "content/common/gpu/client/context_provider_command_buffer.h"
@@ -21,27 +22,35 @@ BrowserCompositorOutputSurface::BrowserCompositorOutputSurface(
     const scoped_refptr<cc::ContextProvider>& context_provider,
     const scoped_refptr<cc::ContextProvider>& worker_context_provider,
     const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager,
+    base::SingleThreadTaskRunner* task_runner,
     scoped_ptr<BrowserCompositorOverlayCandidateValidator>
         overlay_candidate_validator)
     : OutputSurface(context_provider, worker_context_provider),
       vsync_manager_(vsync_manager),
+      synthetic_begin_frame_source_(new cc::SyntheticBeginFrameSource(
+          task_runner,
+          cc::BeginFrameArgs::DefaultInterval())),
       reflector_(nullptr),
       use_begin_frame_scheduling_(
-          base::CommandLine::ForCurrentProcess()
-              ->HasSwitch(cc::switches::kEnableBeginFrameScheduling)) {
+          base::CommandLine::ForCurrentProcess()->HasSwitch(
+              cc::switches::kEnableBeginFrameScheduling)) {
   overlay_candidate_validator_ = std::move(overlay_candidate_validator);
   Initialize();
 }
 
 BrowserCompositorOutputSurface::BrowserCompositorOutputSurface(
     scoped_ptr<cc::SoftwareOutputDevice> software_device,
-    const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager)
+    const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager,
+    base::SingleThreadTaskRunner* task_runner)
     : OutputSurface(std::move(software_device)),
       vsync_manager_(vsync_manager),
+      synthetic_begin_frame_source_(new cc::SyntheticBeginFrameSource(
+          task_runner,
+          cc::BeginFrameArgs::DefaultInterval())),
       reflector_(nullptr),
       use_begin_frame_scheduling_(
-          base::CommandLine::ForCurrentProcess()
-              ->HasSwitch(cc::switches::kEnableBeginFrameScheduling)) {
+          base::CommandLine::ForCurrentProcess()->HasSwitch(
+              cc::switches::kEnableBeginFrameScheduling)) {

[sunnyps, 2016/04/01 22:35:25]

nit: Is this flag ever false? If not can you remove it?

[enne (OOO), 2016/04/02 00:18:38]

Yes.  This flag is sometimes false.  That boolean is used to sometimes send
vsync information to the renderer when it is false.  That vsync path can't be
removed until all the renderers are using begin frame scheduling, unfortunately.

   Initialize();
 }
 
@@ -67,18 +76,34 @@ bool BrowserCompositorOutputSurface::BindToClient(
   if (!OutputSurface::BindToClient(client))
     return false;
 
+  // Pass begin frame source up to Display to use for DisplayScheduler.
+  client->SetBeginFrameSource(synthetic_begin_frame_source_.get());
+
   // Don't want vsync notifications until there is a client.
   if (!use_begin_frame_scheduling_)
     vsync_manager_->AddObserver(this);
   return true;
 }
 
+void BrowserCompositorOutputSurface::UpdateVSyncParametersInternal(
+    base::TimeTicks timebase,
+    base::TimeDelta interval) {
+  if (interval == base::TimeDelta()) {
+    // TODO(brianderson): We should not be receiving 0 intervals.
+    interval = cc::BeginFrameArgs::DefaultInterval();
+  }
+  synthetic_begin_frame_source_->OnUpdateVSyncParameters(timebase, interval);
+
+  // TODO(enne): remove this once vsyncs are no longer used in the renderer.
+  CommitVSyncParameters(timebase, interval);
+}
+
 void BrowserCompositorOutputSurface::OnUpdateVSyncParameters(
     base::TimeTicks timebase,
     base::TimeDelta interval) {
   DCHECK(HasClient());
   DCHECK(!use_begin_frame_scheduling_);
-  CommitVSyncParameters(timebase, interval);
+  UpdateVSyncParametersInternal(timebase, interval);
 }
 
 void BrowserCompositorOutputSurface::OnUpdateVSyncParametersFromGpu(
@@ -86,7 +111,7 @@ void BrowserCompositorOutputSurface::OnUpdateVSyncParametersFromGpu(
     base::TimeDelta interval) {
   DCHECK(HasClient());
   if (use_begin_frame_scheduling_) {
-    CommitVSyncParameters(timebase, interval);
+    UpdateVSyncParametersInternal(timebase, interval);
     return;
   }