Add a new API to create a surfaceless GLSurface for Ozone

ui/gl/gl_surface_ozone.cc

Index: ui/gl/gl_surface_ozone.cc
diff --git a/ui/gl/gl_surface_ozone.cc b/ui/gl/gl_surface_ozone.cc
index cba706bda4e030b6daa599525846ebebbc847640..0ddc1a413b03af6e0cebac38ba8990ce98c83ac6 100644
--- a/ui/gl/gl_surface_ozone.cc
+++ b/ui/gl/gl_surface_ozone.cc
@@ -14,6 +14,8 @@
 #include "ui/gl/gl_surface_osmesa.h"
 #include "ui/gl/gl_surface_stub.h"
 #include "ui/gl/scoped_make_current.h"
+#include "ui/ozone/gpu/gpu_memory_buffer_factory_ozone_native_buffer.h"
+#include "ui/ozone/public/native_pixmap.h"
 #include "ui/ozone/public/surface_factory_ozone.h"
 #include "ui/ozone/public/surface_ozone_egl.h"
 
@@ -157,7 +159,7 @@ class GL_EXPORT GLSurfaceOzoneSurfaceless : public SurfacelessEGL {
     return SwapBuffersAsync(callback);
   }
 
- private:
+ protected:
   ~GLSurfaceOzoneSurfaceless() override {
     Destroy();  // EGL surface must be destroyed before SurfaceOzone
   }
@@ -194,6 +196,93 @@ class GL_EXPORT GLSurfaceOzoneSurfaceless : public SurfacelessEGL {
   DISALLOW_COPY_AND_ASSIGN(GLSurfaceOzoneSurfaceless);
 };
 
+// This provides surface-like semantics implemented through surfaceless.
+// A framebuffer is bound automatically and re-bound at each swap.
+class GL_EXPORT GLSurfaceOzoneSurfacelessSurfaceImpl
+    : public GLSurfaceOzoneSurfaceless {
+ public:
+  GLSurfaceOzoneSurfacelessSurfaceImpl(
+      scoped_ptr<ui::SurfaceOzoneEGL> ozone_surface,
+      AcceleratedWidget widget)
+      : GLSurfaceOzoneSurfaceless(ozone_surface.Pass(), widget),
+        fbo_(0),
+        current_surface_(0) {
+    textures_[0] = 0;
+    textures_[1] = 0;
+  }
+
+  unsigned int GetBackingFrameBufferObject() override { return fbo_; }
+
+  bool OnMakeCurrent(GLContext* context) override {
+    if (!fbo_) {
+      glGenFramebuffersEXT(1, &fbo_);
+      if (!fbo_)
+        return false;
+      glGenTextures(2, textures_);
+      // Create and bind our pixmaps.
+      ResizePixmaps();
+    }
+    BindFramebuffer();
+    return SurfacelessEGL::OnMakeCurrent(context);
+  }
+
+  bool Resize(const gfx::Size& size) override {
+    return GLSurfaceOzoneSurfaceless::Resize(size) && ResizePixmaps();
+  }
+
+  bool SupportsPostSubBuffer() override { return false; }
+
+  bool SwapBuffers() override {
+    bool ret = images_[current_surface_]->ScheduleOverlayPlane(
+                   widget_, 0, OverlayTransform::OVERLAY_TRANSFORM_NONE,
+                   gfx::Rect(GetSize()), gfx::RectF(1, 1)) &&
+               GLSurfaceOzoneSurfaceless::SwapBuffers();
+    current_surface_ ^= 1;
+    BindFramebuffer();
+    return ret;
+  }
+
+ private:
+  ~GLSurfaceOzoneSurfacelessSurfaceImpl() override {
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    glDeleteTextures(2, textures_);
+    glDeleteFramebuffers(1, &fbo_);
+  }
+
+  void BindFramebuffer() {
+    glBindFramebufferEXT(GL_FRAMEBUFFER, fbo_);
+    glFramebufferTexture2DEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+                              GL_TEXTURE_2D, textures_[current_surface_], 0);
+  }
+
+  bool ResizePixmaps() {
+    if (!fbo_)
+      return true;
+    for (int i = 0; i < 2; i++) {
+      scoped_refptr<ui::NativePixmap> pixmap =
+          ui::SurfaceFactoryOzone::GetInstance()->CreateNativePixmap(
+              widget_, GetSize(), ui::SurfaceFactoryOzone::RGBA_8888,
+              ui::SurfaceFactoryOzone::SCANOUT);
+      if (!pixmap)
+        return false;
+      images_[i] =
+          ui::GpuMemoryBufferFactoryOzoneNativeBuffer::CreateImageForPixmap(
+              pixmap, GetSize(), GpuMemoryBuffer::Format::RGBA_8888, GL_RGBA);
+      // Bind image to texture
+      glBindTexture(GL_TEXTURE_EXTERNAL_OES, textures_[i]);
+      if (!images_[i]->BindTexImage(GL_TEXTURE_EXTERNAL_OES))
+        return false;
+    }
+    return true;
+  }
+
+  GLuint fbo_;
+  GLuint textures_[2];
+  scoped_refptr<GLImage> images_[2];
+  int current_surface_;
+  DISALLOW_COPY_AND_ASSIGN(GLSurfaceOzoneSurfacelessSurfaceImpl);
+};
+
 }  // namespace
 
 // static
@@ -215,6 +304,27 @@ bool GLSurface::InitializeOneOffInternal() {
 }
 
 // static
+scoped_refptr<GLSurface> GLSurface::CreateSurfacelessViewGLSurface(
+    gfx::AcceleratedWidget window) {
+  if (GetGLImplementation() == kGLImplementationEGLGLES2 &&
+      window != kNullAcceleratedWidget &&
+      GLSurfaceEGL::IsEGLSurfacelessContextSupported() &&
+      ui::SurfaceFactoryOzone::GetInstance()->CanShowPrimaryPlaneAsOverlay()) {
+    scoped_ptr<ui::SurfaceOzoneEGL> surface_ozone =
+        ui::SurfaceFactoryOzone::GetInstance()
+            ->CreateSurfacelessEGLSurfaceForWidget(window);
+    if (!surface_ozone)
+      return NULL;
+    scoped_refptr<GLSurface> surface;
+    surface = new GLSurfaceOzoneSurfaceless(surface_ozone.Pass(), window);
+    if (surface->Initialize())
+      return surface;
+  }
+
+  return nullptr;
+}
+
+// static
 scoped_refptr<GLSurface> GLSurface::CreateViewGLSurface(
     gfx::AcceleratedWidget window) {
   if (GetGLImplementation() == kGLImplementationOSMesaGL) {
@@ -234,7 +344,8 @@ scoped_refptr<GLSurface> GLSurface::CreateViewGLSurface(
               ->CreateSurfacelessEGLSurfaceForWidget(window);
       if (!surface_ozone)
         return NULL;
-      surface = new GLSurfaceOzoneSurfaceless(surface_ozone.Pass(), window);
+      surface = new GLSurfaceOzoneSurfacelessSurfaceImpl(surface_ozone.Pass(),
+                                                         window);
     } else {
       scoped_ptr<ui::SurfaceOzoneEGL> surface_ozone =
           ui::SurfaceFactoryOzone::GetInstance()->CreateEGLSurfaceForWidget(