ui: Use single buffer SurfaceTexture mode for native GpuMemoryBuffers on Android.

content/common/gpu/gpu_memory_buffer_factory_surface_texture.cc

Index: content/common/gpu/gpu_memory_buffer_factory_surface_texture.cc
diff --git a/content/common/gpu/gpu_memory_buffer_factory_surface_texture.cc b/content/common/gpu/gpu_memory_buffer_factory_surface_texture.cc
index a4cf15ed30ede039e8bc3e14ba3cd46f1a8a9359..ac79ef93e7d11dae10d0f7e625ea471c77cf255b 100644
--- a/content/common/gpu/gpu_memory_buffer_factory_surface_texture.cc
+++ b/content/common/gpu/gpu_memory_buffer_factory_surface_texture.cc
@@ -6,7 +6,9 @@
 
 #include "content/common/android/surface_texture_manager.h"
 #include "ui/gl/android/surface_texture.h"
+#include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_image_surface_texture.h"
+#include "ui/gl/scoped_binders.h"
 
 namespace content {
 
@@ -23,8 +25,8 @@ bool GpuMemoryBufferFactorySurfaceTexture::
   switch (usage) {
     case gfx::BufferUsage::GPU_READ:
     case gfx::BufferUsage::SCANOUT:
-    case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT:
       return false;
+    case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT:
     case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       return format == gfx::BufferFormat::RGBA_8888;
   }
@@ -40,13 +42,14 @@ GpuMemoryBufferFactorySurfaceTexture::CreateGpuMemoryBuffer(
     gfx::BufferUsage usage,
     int client_id,
     gfx::PluginWindowHandle surface_handle) {
-  // Note: this needs to be 0 as the surface texture implemenation will take
-  // ownership of the texture and call glDeleteTextures when the GPU service
-  // attaches the surface texture to a real texture id. glDeleteTextures
-  // silently ignores 0.
+  // This can be called on a thread without a GL context current so use a dummy
+  // texture id instread of a real one.
+  // Note: This needs to be 0 as the surface texture implemenation will take
+  // ownership of the texture and call glDeleteTextures when we attach a real
+  // texture id to it. See CreateImageForGpuMemoryBuffer() below.
   const int kDummyTextureId = 0;
   scoped_refptr<gfx::SurfaceTexture> surface_texture =
-      gfx::SurfaceTexture::Create(kDummyTextureId);
+      gfx::SurfaceTexture::CreateSingleBuffered(kDummyTextureId);
   if (!surface_texture.get())
     return gfx::GpuMemoryBufferHandle();
 
@@ -111,12 +114,34 @@ GpuMemoryBufferFactorySurfaceTexture::CreateImageForGpuMemoryBuffer(
   SurfaceTextureMapKey key(handle.id.id, client_id);
   SurfaceTextureMap::iterator it = surface_textures_.find(key);
   if (it == surface_textures_.end())
-    return scoped_refptr<gl::GLImage>();
+    return nullptr;
+
+  gfx::SurfaceTexture* surface_texture = it->second.get();
+  // Note: Surface textures used as gpu memory buffers are created with an
+  // initial dummy texture id of 0. We need to call DetachFromGLContext() here
+  // to detach from the dummy texture before we can attach to a real texture
+  // id. DetachFromGLContext() will delete the texture for the current
+  // attachment point. Detaching from the dummy texture id should not cause any
+  // problems as the GL should silently ignore 0 when passed to
+  // glDeleteTextures.
+  surface_texture->DetachFromGLContext();
+
+  // Create a real texture.
+  GLuint texture_id = 0;
+  glGenTextures(1, &texture_id);
+  DCHECK(texture_id);
+  {
+    gfx::ScopedTextureBinder texture_binder(GL_TEXTURE_EXTERNAL_OES,
+                                            texture_id);
+    // This will attach the surface texture to the texture currently bound to
+    // GL_TEXTURE_EXTERNAL_OES target and take ownership of the texture.
+    surface_texture->AttachToGLContext();
+  }
 
   scoped_refptr<gl::GLImageSurfaceTexture> image(
       new gl::GLImageSurfaceTexture(size));
-  if (!image->Initialize(it->second.get()))
-    return scoped_refptr<gl::GLImage>();
+  if (!image->Initialize(surface_texture))
+    return nullptr;
 
   return image;
 }