Add FBO support in Android WebView

content/browser/android/in_process/synchronous_compositor_output_surface.cc

Index: content/browser/android/in_process/synchronous_compositor_output_surface.cc
diff --git a/content/browser/android/in_process/synchronous_compositor_output_surface.cc b/content/browser/android/in_process/synchronous_compositor_output_surface.cc
index fafd06fda22c7268b4f5d38024cee0196389259e..1992c8dc81f319dc38fc7341d75fc0c02773d03f 100644
--- a/content/browser/android/in_process/synchronous_compositor_output_surface.cc
+++ b/content/browser/android/in_process/synchronous_compositor_output_surface.cc
@@ -15,6 +15,7 @@
 #include "content/browser/android/in_process/synchronous_compositor_impl.h"
 #include "content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h"
 #include "content/public/browser/browser_thread.h"
+#include "gpu/command_buffer/client/gl_in_process_context.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "ui/gfx/rect_conversions.h"
@@ -23,22 +24,58 @@
 #include "ui/gl/gl_context.h"
 #include "webkit/common/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h"
 
-using webkit::gpu::WebGraphicsContext3DInProcessCommandBufferImpl;
 
 namespace content {
 
 namespace {
 
-// TODO(boliu): RenderThreadImpl should create in process contexts as well.
-scoped_ptr<WebKit::WebGraphicsContext3D> CreateWebGraphicsContext3D() {
+scoped_ptr<WebKit::WebGraphicsContext3D> CreateWebGraphicsContext3D(
+    scoped_refptr<gfx::GLSurface> surface) {
+  using webkit::gpu::WebGraphicsContext3DInProcessCommandBufferImpl;
+  if (!gfx::GLSurface::InitializeOneOff())
+    scoped_ptr<WebKit::WebGraphicsContext3D>();
+
+  // TODO(boliu): Much of this code is copied or adapted from
+  // WebGraphicsContext3DInProcessCommandBufferImpl. Refactor and reduce
+  // code duplication.
+  const bool offscreen = false;
+  const gfx::Size size(1, 1);
+  const char* allowed_extensions = "*";
+  const gfx::GpuPreference gpu_preference = gfx::PreferDiscreteGpu;
+
   WebKit::WebGraphicsContext3D::Attributes attributes;
   attributes.antialias = false;
   attributes.shareResources = true;
   attributes.noAutomaticFlushes = true;
+  const int alpha_size = attributes.alpha ? 8 : 0;
+  const int depth_size = attributes.depth ? 24 : 0;
+  const int stencil_size = attributes.stencil ? 8 : 0;
+  const int samples = attributes.antialias ? 4 : 0;
+  const int sample_buffers = attributes.antialias ? 1 : 0;
+  const int32 attribs[] = {
+    gpu::GLInProcessContext::ALPHA_SIZE, alpha_size,
+    gpu::GLInProcessContext::DEPTH_SIZE, depth_size,
+    gpu::GLInProcessContext::STENCIL_SIZE, stencil_size,
+    gpu::GLInProcessContext::SAMPLES, samples,
+    gpu::GLInProcessContext::SAMPLE_BUFFERS, sample_buffers,
+    gpu::GLInProcessContext::NONE,
+  };
+
+  scoped_ptr<gpu::GLInProcessContext> context(
+      gpu::GLInProcessContext::CreateWithSurface(surface,
+                                                 offscreen,
+                                                 size,
+                                                 attributes.shareResources,
+                                                 allowed_extensions,
+                                                 attribs,
+                                                 gpu_preference));
+
+  if (!context.get())
+    scoped_ptr<WebKit::WebGraphicsContext3D>();
 
   return scoped_ptr<WebKit::WebGraphicsContext3D>(
-      WebGraphicsContext3DInProcessCommandBufferImpl
-          ::CreateViewContext(attributes, NULL));
+      WebGraphicsContext3DInProcessCommandBufferImpl::WrapContext(
+          context.Pass(), attributes));
 }
 
 void DidActivatePendingTree(int routing_id) {
@@ -180,13 +217,21 @@ bool SynchronousCompositorOutputSurface::InitializeHwDraw(
   DCHECK(CalledOnValidThread());
   DCHECK(HasClient());
   DCHECK(!context3d_);
+  DCHECK(!surface_);
+
+  surface_ = new gfx::GLSurfaceStub;
+  bool success = InitializeAndSetContext3D(
+      CreateWebGraphicsContext3D(surface_).Pass(), offscreen_context);
+  if (!success)
+    surface_ = NULL;
 
-  return InitializeAndSetContext3D(CreateWebGraphicsContext3D().Pass(),
-                                   offscreen_context);
+  return success;
 }
 
 void SynchronousCompositorOutputSurface::ReleaseHwDraw() {
+  DCHECK(surface_);
   cc::OutputSurface::ReleaseGL();
+  surface_ = NULL;
 }
 
 bool SynchronousCompositorOutputSurface::DemandDrawHw(
@@ -197,6 +242,9 @@ bool SynchronousCompositorOutputSurface::DemandDrawHw(
   DCHECK(CalledOnValidThread());
   DCHECK(HasClient());
   DCHECK(context3d());
+  DCHECK(surface_);
+
+  surface_->SaveCurrentFBO();
 
   gfx::Transform adjusted_transform = transform;
   AdjustTransformForClip(&adjusted_transform, clip);
@@ -205,8 +253,6 @@ bool SynchronousCompositorOutputSurface::DemandDrawHw(
   SetExternalStencilTest(stencil_enabled);
   InvokeComposite(clip.size());
 
-  // TODO(boliu): Check if context is lost here.
-
   return did_swap_buffer_;
 }