Drop frontbuffers with ui-use-gpu-process, synchronized with browser, decoupled from backbuffer dro…

content/common/gpu/image_transport_surface_linux.cc

Index: content/common/gpu/image_transport_surface_linux.cc
diff --git a/content/common/gpu/image_transport_surface_linux.cc b/content/common/gpu/image_transport_surface_linux.cc
index 90341b5b0c25d83a8289dd37413aaaf76fbf8f53..11ecae4e9ef5d51d35f06f77d6927e6c3fcf8215 100644
--- a/content/common/gpu/image_transport_surface_linux.cc
+++ b/content/common/gpu/image_transport_surface_linux.cc
@@ -93,7 +93,8 @@ class EGLImageTransportSurface
   virtual gfx::Size GetSize() OVERRIDE;
   virtual bool OnMakeCurrent(gfx::GLContext* context) OVERRIDE;
   virtual unsigned int GetBackingFrameBufferObject() OVERRIDE;
-  virtual void SetBufferAllocation(BufferAllocationState state) OVERRIDE;
+  virtual void SetBackbufferAllocation(bool allocated) OVERRIDE;
+  virtual void SetFrontbufferAllocation(bool allocated) OVERRIDE;
 
  protected:
   // ImageTransportSurface implementation
@@ -102,6 +103,7 @@ class EGLImageTransportSurface
   virtual void OnBuffersSwappedACK() OVERRIDE;
   virtual void OnPostSubBufferACK() OVERRIDE;
   virtual void OnResizeViewACK() OVERRIDE;
+  virtual void OnDiscardSurface(uint64 surface_id) OVERRIDE;
   virtual void OnResize(gfx::Size size) OVERRIDE;
 
  private:
@@ -111,7 +113,8 @@ class EGLImageTransportSurface
   void SendPostSubBuffer(int x, int y, int width, int height);
 
   // Tracks the current buffer allocation state.
-  BufferAllocationState buffer_allocation_state_;
+  bool backbuffer_allocated_;
+  bool frontbuffer_allocated_;
 
   uint32 fbo_id_;
 
@@ -145,7 +148,8 @@ class GLXImageTransportSurface
   virtual std::string GetExtensions();
   virtual gfx::Size GetSize() OVERRIDE;
   virtual bool OnMakeCurrent(gfx::GLContext* context) OVERRIDE;
-  virtual void SetBufferAllocation(BufferAllocationState state) OVERRIDE;
+  virtual void SetBackbufferAllocation(bool allocated) OVERRIDE;
+  virtual void SetFrontbufferAllocation(bool allocated) OVERRIDE;
 
  protected:
   // ImageTransportSurface implementation:
@@ -154,6 +158,7 @@ class GLXImageTransportSurface
   virtual void OnBuffersSwappedACK() OVERRIDE;
   virtual void OnPostSubBufferACK() OVERRIDE;
   virtual void OnResizeViewACK() OVERRIDE;
+  virtual void OnDiscardSurface(uint64 surface_id) OVERRIDE;
   virtual void OnResize(gfx::Size size) OVERRIDE;
 
  private:
@@ -168,7 +173,8 @@ class GLXImageTransportSurface
   void ResizeSurface(gfx::Size size);
 
   // Tracks the current buffer allocation state.
-  BufferAllocationState buffer_allocation_state_;
+  bool backbuffer_allocated_;
+  bool frontbuffer_allocated_;
 
   XID dummy_parent_;
   gfx::Size size_;
@@ -212,6 +218,7 @@ class OSMesaImageTransportSurface : public ImageTransportSurface,
   virtual void OnBuffersSwappedACK() OVERRIDE;
   virtual void OnPostSubBufferACK() OVERRIDE;
   virtual void OnResizeViewACK() OVERRIDE;
+  virtual void OnDiscardSurface(uint64 surface_id) OVERRIDE;
   virtual void OnResize(gfx::Size size) OVERRIDE;
 
  private:
@@ -270,7 +277,8 @@ EGLImageTransportSurface::EGLImageTransportSurface(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub)
     : gfx::PbufferGLSurfaceEGL(false, gfx::Size(16, 16)),
-      buffer_allocation_state_(BUFFER_ALLOCATION_FRONT_AND_BACK),
+      backbuffer_allocated_(true),
+      frontbuffer_allocated_(true),
       fbo_id_(0),
       made_current_(false) {
   helper_.reset(new ImageTransportHelper(this,
@@ -336,33 +344,27 @@ unsigned int EGLImageTransportSurface::GetBackingFrameBufferObject() {
   return fbo_id_;
 }
 
-void EGLImageTransportSurface::SetBufferAllocation(
-    BufferAllocationState state) {
-  if (buffer_allocation_state_ == state)
+void EGLImageTransportSurface::SetBackbufferAllocation(bool allocated) {
+  if (backbuffer_allocated_ == allocated)
+    return;
+  // TODO(mmocny): Remove dependancy on front_surface_->size()
+  if (!front_surface_.get())
     return;
-  buffer_allocation_state_ = state;
-
-  switch (state) {
-    case BUFFER_ALLOCATION_FRONT_AND_BACK:
-      if (!back_surface_.get() && front_surface_.get())
-        OnResize(front_surface_->size());
-      break;
-
-    case BUFFER_ALLOCATION_FRONT_ONLY:
-      if (back_surface_.get() && front_surface_.get())
-        ReleaseSurface(&back_surface_);
-      break;
-
-    case BUFFER_ALLOCATION_NONE:
-      if (back_surface_.get() && front_surface_.get())
-        ReleaseSurface(&back_surface_);
-      break;
 
-    default:
-      NOTREACHED();
+  if (allocated) {
+    if (!back_surface_.get())
+      OnResize(front_surface_->size());
+    backbuffer_allocated_ = true;
+  } else {
+    if (back_surface_.get())
+      ReleaseSurface(&back_surface_);
+    backbuffer_allocated_ = false;
   }
 }
 
+void EGLImageTransportSurface::SetFrontbufferAllocation(bool allocated) {
+}
+
 void EGLImageTransportSurface::ReleaseSurface(
     scoped_refptr<EGLAcceleratedSurface>* surface) {
   if (surface->get()) {
@@ -399,6 +401,8 @@ void EGLImageTransportSurface::OnResize(gfx::Size size) {
 }
 
 bool EGLImageTransportSurface::SwapBuffers() {
+  DCHECK(backbuffer_allocated_);
+  DCHECK(frontbuffer_allocated_);
   front_surface_.swap(back_surface_);
   DCHECK_NE(front_surface_.get(), static_cast<EGLAcceleratedSurface*>(NULL));
   helper_->DeferToFence(base::Bind(
@@ -428,7 +432,8 @@ void EGLImageTransportSurface::SendBuffersSwapped() {
 
 bool EGLImageTransportSurface::PostSubBuffer(
     int x, int y, int width, int height) {
-
+  DCHECK(backbuffer_allocated_);
+  DCHECK(frontbuffer_allocated_);
   DCHECK_NE(back_surface_.get(), static_cast<EGLAcceleratedSurface*>(NULL));
   gfx::Size expected_size = back_surface_->size();
   bool surfaces_same_size = front_surface_.get() &&
@@ -511,6 +516,10 @@ void EGLImageTransportSurface::OnNewSurfaceACK(
   helper_->SetScheduled(true);
 }
 
+void EGLImageTransportSurface::OnDiscardSurface(
+    uint64 surface_id) {
+}
+
 void EGLImageTransportSurface::OnBuffersSwappedACK() {
   helper_->SetScheduled(true);
 }
@@ -527,7 +536,8 @@ GLXImageTransportSurface::GLXImageTransportSurface(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub)
     : gfx::NativeViewGLSurfaceGLX(),
-      buffer_allocation_state_(BUFFER_ALLOCATION_FRONT_AND_BACK),
+      backbuffer_allocated_(true),
+      frontbuffer_allocated_(true),
       dummy_parent_(0),
       size_(1, 1),
       bound_(false),
@@ -611,32 +621,24 @@ void GLXImageTransportSurface::ReleaseSurface() {
   bound_ = false;
 }
 
-void GLXImageTransportSurface::SetBufferAllocation(
-    BufferAllocationState state) {
-  if (buffer_allocation_state_ == state)
+void GLXImageTransportSurface::SetBackbufferAllocation(bool allocated) {
+  if (backbuffer_allocated_ == allocated)
     return;
-  buffer_allocation_state_ = state;
 
-  switch (state) {
-    case BUFFER_ALLOCATION_FRONT_AND_BACK: {
-      ResizeSurface(size_);
-      break;
-    }
-    case BUFFER_ALLOCATION_FRONT_ONLY: {
-      ResizeSurface(gfx::Size(1,1));
-      break;
-    }
-    case BUFFER_ALLOCATION_NONE: {
-      ResizeSurface(gfx::Size(1,1));
-      if (bound_)
-        ReleaseSurface();
-      break;
-    }
-    default:
-      NOTREACHED();
+  if (allocated) {
+    // cannot allocate backbuffer without also allocating a frontbuffer.
+    ResizeSurface(size_);
+    backbuffer_allocated_ = true;
+    frontbuffer_allocated_ = true;
+  } else {
+    ResizeSurface(gfx::Size(1,1));
+    backbuffer_allocated_ = false;
   }
 }
 
+void GLXImageTransportSurface::SetFrontbufferAllocation(bool allocated) {
+}
+
 void GLXImageTransportSurface::ResizeSurface(gfx::Size size) {
   Display* dpy = static_cast<Display*>(GetDisplay());
   XResizeWindow(dpy, window_, size.width(), size.height());
@@ -656,6 +658,8 @@ void GLXImageTransportSurface::OnResize(gfx::Size size) {
 }
 
 bool GLXImageTransportSurface::SwapBuffers() {
+  DCHECK(backbuffer_allocated_);
+  DCHECK(frontbuffer_allocated_);
   gfx::NativeViewGLSurfaceGLX::SwapBuffers();
   helper_->DeferToFence(base::Bind(
       &GLXImageTransportSurface::SendBuffersSwapped,
@@ -682,6 +686,8 @@ void GLXImageTransportSurface::SendBuffersSwapped() {
 
 bool GLXImageTransportSurface::PostSubBuffer(
     int x, int y, int width, int height) {
+  DCHECK(backbuffer_allocated_);
+  DCHECK(frontbuffer_allocated_);
   gfx::NativeViewGLSurfaceGLX::PostSubBuffer(x, y, width, height);
   helper_->DeferToFence(base::Bind(
       &GLXImageTransportSurface::SendPostSubBuffer,
@@ -749,6 +755,10 @@ void GLXImageTransportSurface::OnNewSurfaceACK(
     uint64 surface_handle, TransportDIB::Handle /*shm_handle*/) {
 }
 
+void GLXImageTransportSurface::OnDiscardSurface(
+    uint64 surface_id) {
+}
+
 void GLXImageTransportSurface::OnBuffersSwappedACK() {
   helper_->SetScheduled(true);
 }
@@ -835,6 +845,10 @@ void OSMesaImageTransportSurface::OnNewSurfaceACK(
   helper_->SetScheduled(true);
 }
 
+void OSMesaImageTransportSurface::OnDiscardSurface(
+    uint64 surface_id) {
+}
+
 void OSMesaImageTransportSurface::OnResizeViewACK() {
   NOTREACHED();
 }