cc: Emulate BeginFrame in OutputSurfaces that don't support it natively

cc/output/output_surface.cc

Index: cc/output/output_surface.cc
diff --git a/cc/output/output_surface.cc b/cc/output/output_surface.cc
index fe2b074ee46d033f7900054ccb164dc3b3992cae..4ffdc42cff590e9ea3166c28a34621d9bfa48b4b 100644
--- a/cc/output/output_surface.cc
+++ b/cc/output/output_surface.cc
@@ -8,10 +8,12 @@
 #include <string>
 #include <vector>
 
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "base/strings/string_split.h"
 #include "cc/output/output_surface_client.h"
+#include "cc/scheduler/delay_based_time_source.h"
 #include "third_party/WebKit/public/platform/WebGraphicsContext3D.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "third_party/khronos/GLES2/gl2ext.h"
@@ -29,7 +31,7 @@ class OutputSurfaceCallbacks
         WebGraphicsSwapBuffersCompleteCallbackCHROMIUM,
       public WebKit::WebGraphicsContext3D::WebGraphicsContextLostCallback {
  public:
-  explicit OutputSurfaceCallbacks(OutputSurfaceClient* client)
+  explicit OutputSurfaceCallbacks(OutputSurface* client)
       : client_(client) {}
 
   // WK:WGC3D::WGSwapBuffersCompleteCallbackCHROMIUM implementation.
@@ -39,21 +41,27 @@ class OutputSurfaceCallbacks
   virtual void onContextLost() { client_->DidLoseOutputSurface(); }
 
  private:
-  OutputSurfaceClient* client_;
+  OutputSurface* client_;
 };
 
 OutputSurface::OutputSurface(
     scoped_ptr<WebKit::WebGraphicsContext3D> context3d)
     : client_(NULL),
       context3d_(context3d.Pass()),
-      has_gl_discard_backbuffer_(false) {
+      has_gl_discard_backbuffer_(false),
+      max_frames_pending_(0),
+      pending_swap_buffers_(0),
+      begin_frame_pending_(false) {
 }
 
 OutputSurface::OutputSurface(
     scoped_ptr<cc::SoftwareOutputDevice> software_device)
     : client_(NULL),
       software_device_(software_device.Pass()),
-      has_gl_discard_backbuffer_(false) {
+      has_gl_discard_backbuffer_(false),
+      max_frames_pending_(0),
+      pending_swap_buffers_(0),
+      begin_frame_pending_(false) {
 }
 
 OutputSurface::OutputSurface(
@@ -62,18 +70,115 @@ OutputSurface::OutputSurface(
     : client_(NULL),
       context3d_(context3d.Pass()),
       software_device_(software_device.Pass()),
-      has_gl_discard_backbuffer_(false) {
+      has_gl_discard_backbuffer_(false),
+      max_frames_pending_(0),
+      pending_swap_buffers_(0),
+      begin_frame_pending_(false) {
+}
+
+void OutputSurface::InitializeBeginFrameEmulation(
+    Thread* thread,
+    bool throttle_frame_production,
+    base::TimeDelta interval,
+    bool swap_buffers_complete_supported) {
+  DCHECK(!frame_rate_controller_);
+  if (throttle_frame_production){
+    frame_rate_controller_.reset(
+        new FrameRateController(
+            DelayBasedTimeSource::Create(interval, thread)));
+  } else {
+    frame_rate_controller_.reset(new FrameRateController(thread));
+  }
+
+  frame_rate_controller_->SetClient(this);
+  frame_rate_controller_->SetSwapBuffersCompleteSupported(
+      swap_buffers_complete_supported);
+  frame_rate_controller_->SetMaxSwapsPending(max_frames_pending_);
+}
+
+void OutputSurface::SetMaxFramesPending(int max_frames_pending) {
+  if (frame_rate_controller_)
+    frame_rate_controller_->SetMaxSwapsPending(max_frames_pending);
+  max_frames_pending_ = max_frames_pending;
+}
+
+void OutputSurface::OnVSyncParametersChanged(base::TimeTicks timebase,
+                                             base::TimeDelta interval) {
+  TRACE_EVENT2("cc", "OutputSurface::OnVSyncParametersChanged",
+               "timebase", (timebase - base::TimeTicks()).InSecondsF(),
+               "interval", interval.InSecondsF());
+  if (frame_rate_controller_)
+    frame_rate_controller_->SetTimebaseAndInterval(timebase, interval);
+}
+
+void OutputSurface::FrameRateControllerTick(bool throttled) {
+  DCHECK(frame_rate_controller_);
+  if (!throttled)
+    BeginFrame(frame_rate_controller_->LastTickTime());
+}
+
+// Forwarded to OutputSurfaceClient
+void OutputSurface::SetNeedsRedrawRect(gfx::Rect damage_rect) {
+  TRACE_EVENT0("cc", "OutputSurface::SetNeedsRedrawRect");
+  client_->SetNeedsRedrawRect(damage_rect);
+}
+
+void OutputSurface::SetNeedsBeginFrame(bool enable) {
+  begin_frame_pending_ = false;
+  if (frame_rate_controller_)
+    frame_rate_controller_->SetActive(enable);
+}
+
+void OutputSurface::BeginFrame(base::TimeTicks frame_time) {
+  // TODO(brianderson): Remove this early return once Android has
+  // Browser-side throttling.
+  if (begin_frame_pending_ || pending_swap_buffers_ >= max_frames_pending_)
+    return;
+  TRACE_EVENT0("cc", "OutputSurface::BeginFrame");
+  begin_frame_pending_ = true;
+  client_->BeginFrame(frame_time);
+}
+
+void OutputSurface::OnSendFrameToParentCompositorAck(
+    const CompositorFrameAck& ack) {
+  TRACE_EVENT0("cc", "OutputSurface::OnSendFrameToParentCompositorAck");
+  client_->OnSendFrameToParentCompositorAck(ack);
+}
+
+void OutputSurface::DidSwapBuffers() {
+  begin_frame_pending_ = false;
+  pending_swap_buffers_++;
+  if (frame_rate_controller_)
+    frame_rate_controller_->DidSwapBuffers();
+}
+
+void OutputSurface::OnSwapBuffersComplete() {
+  TRACE_EVENT0("cc", "OutputSurface::OnSwapBuffersComplete");
+  pending_swap_buffers_--;
+  client_->OnSwapBuffersComplete();
+  if (frame_rate_controller_)
+    frame_rate_controller_->DidSwapBuffersComplete();
+}
+
+void OutputSurface::DidLoseOutputSurface() {
+  TRACE_EVENT0("cc", "OutputSurface::DidLoseOutputSurface");
+  begin_frame_pending_ = false;
+  pending_swap_buffers_ = 0;
+  client_->DidLoseOutputSurface();
+  if (frame_rate_controller_)
+    frame_rate_controller_->DidAbortAllPendingFrames();
 }
 
 OutputSurface::~OutputSurface() {
+  if (frame_rate_controller_)
+    frame_rate_controller_->SetActive(false);
 }
 
 bool OutputSurface::ForcedDrawToSoftwareDevice() const {
   return false;
 }
 
-bool OutputSurface::BindToClient(
-    cc::OutputSurfaceClient* client) {
+bool OutputSurface::BindToClient(cc::OutputSurfaceClient* client) {
   DCHECK(client);
   if (context3d_ && !context3d_->makeContextCurrent())
     return false;
@@ -88,7 +193,7 @@ bool OutputSurface::BindToClient(
   has_gl_discard_backbuffer_ =
       extensions.count("GL_CHROMIUM_discard_backbuffer") > 0;
 
-  callbacks_.reset(new OutputSurfaceCallbacks(client_));
+  callbacks_.reset(new OutputSurfaceCallbacks(this));
   context3d_->setSwapBuffersCompleteCallbackCHROMIUM(callbacks_.get());
   context3d_->setContextLostCallback(callbacks_.get());
 
@@ -126,6 +231,7 @@ void OutputSurface::SwapBuffers(const ui::LatencyInfo& latency_info) {
   // Note that currently this has the same effect as SwapBuffers; we should
   // consider exposing a different entry point on WebGraphicsContext3D.
   context3d_->prepareTexture();
+  DidSwapBuffers();
 }
 
 void OutputSurface::PostSubBuffer(gfx::Rect rect,
@@ -133,6 +239,7 @@ void OutputSurface::PostSubBuffer(gfx::Rect rect,
   DCHECK(context3d_);
   context3d_->postSubBufferCHROMIUM(
       rect.x(), rect.y(), rect.width(), rect.height());
+  DidSwapBuffers();
 }
 
 }  // namespace cc