Plumb ScheduleOverlayPlane into the GPU process.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_schedule_overlay_plane.txt

+Name
+
+    CHROMIUM_schedule_overlay_plane
+
+Name Strings
+
+    GL_CHROMIUM_schedule_overlay_plane
+
+Version
+
+    Last Modified Date: April 2, 2014
+
+Dependencies
+
+    OpenGL ES 2.0 is required.
+
+Overview
+
+    This extension allows a client to request a texture be presented as a
+    hardware overlay plane along with the framebuffer. The expectation is that
+    all the planes scheduled since the last call to glSwapBuffers or
+    glPostSubBufferCHROMIUM are displayed atomically with the framebuffer during
+    the next call to swap buffers. Scheduled planes are not stateful and need
+    to be rescheduled after the buffers were swapped.
+
+    This extension could be used in conjunction with OES_EGL_image_external
+    to render into buffers suitable for scanout and present them directly
+    via display hardware without further compositing in GLES.
+
+    An example use case would be displaying a video buffer which was decoded by
+    dedicated hardware as part of a GLES application.
+
+Issues
+
+    None
+
+New Tokens
+
+    None
+
+New Procedures and Functions
+
+    The command
+
+        glScheduleOverlayPlaneCHROMIUM (GLint plane_z_order,
+                                        GLenum plane_transform,
+                                        GLuint overlay_texture_id,
+                                        GLint bounds_x,
+                                        GLint bounds_y,
+                                        GLint bounds_width,
+                                        GLint bounds_height,
+                                        GLfloat uv_x,
+                                        GLfloat uv_y,
+                                        GLfloat uv_width,
+                                        GLfloat uv_height);
+
+    Sets the overlay plane to be presented synchronously along with the primary
+    framebuffer during the call to swap buffers.
+    <plane_z_order> specifies the stacking order of the plane relative to the
+    main framebuffer located at index 0.
+    <plane_transform> specifies how the buffer is to be transformed during
+    composition.
+    <overlay_texture_id> is the buffer to be presented by the overlay.
+    <bounds_x>, <bounds_y>, <bounds_width>, <bounds_height> specify where it is
+    supposed to be on the screen.
+    <uv_x>, <uv_y>, <uv_width>, <uv_height> specify the region within the
+    buffer to be placed inside the bounds.
+
+Errors
+
+    None.
+
+New State
+
+    None.