Bug 1962966 - Add offset handling to eglCreatePbufferFromClientBuffer() r=gfx-reviewers,lsalzman

Add the following attributes handling
- EGL_TEXTURE_OFFSET_X_ANGLE
- EGL_TEXTURE_OFFSET_Y_ANGLE

Differential Revision: https://phabricator.services.mozilla.com/D247213

gfx/gl/GLConsts.h

@@ -6610,6 +6610,8 @@
 #define LOCAL_EGL_YUV_SUBSAMPLE_EXT                          0x3312
 #define LOCAL_EGL_Y_AXIS_NV                                  0x3370
 #define LOCAL_EGL_Y_INVERTED_NOK                             0x307F
+#define LOCAL_EGL_TEXTURE_OFFSET_X_ANGLE                     0x3490
+#define LOCAL_EGL_TEXTURE_OFFSET_Y_ANGLE                     0x3491
 
 // GLX
 #define LOCAL_GLX_3DFX_FULLSCREEN_MODE_MESA                  0x2

gfx/webrender_bindings/DCLayerTree.cpp

@@ -1650,8 +1650,15 @@ void DCLayerCompositionSurface::Bind() {
   const auto& gle = gl::GLContextEGL::Cast(gl);
   const auto& egl = gle->mEgl;
 
-  const EGLint pbuffer_attribs[]{LOCAL_EGL_WIDTH, mSize.width, LOCAL_EGL_HEIGHT,
-                                 mSize.height, LOCAL_EGL_NONE};
+  const EGLint pbuffer_attribs[]{LOCAL_EGL_WIDTH,
+                                 mSize.width,
+                                 LOCAL_EGL_HEIGHT,
+                                 mSize.height,
+                                 LOCAL_EGL_TEXTURE_OFFSET_X_ANGLE,
+                                 offset.x,
+                                 LOCAL_EGL_TEXTURE_OFFSET_Y_ANGLE,
+                                 offset.y,
+                                 LOCAL_EGL_NONE};
   const auto buffer = reinterpret_cast<EGLClientBuffer>(backBuffer.get());
   EGLConfig eglConfig = mDCLayerTree->GetEGLConfig();