Do not allocate depth-stencil buffers for GLSurfaces.

We don't need them here. Whenever we need a depth-stencil buffer, it's as a renderbuffer attached to a non-default FBO.

This will save some video memory.

Review URL: http://codereview.chromium.org/7598013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95964 0039d316-1c4b-4281-b951-d872f2087c98

ui/gfx/gl/gl_context_osmesa.cc

@@ -30,8 +30,8 @@ bool GLContextOSMesa::Initialize(GLSurface* compatible_surface) {
   GLuint format =
       static_cast<GLSurfaceOSMesa*>(compatible_surface)->GetFormat();
   context_ = OSMesaCreateContextExt(format,
-                                    24,  // depth bits
-                                    8,  // stencil bits
+                                    0,  // depth bits
+                                    0,  // stencil bits
                                     0,  // accum bits
                                     share_handle);
   if (!context_) {

ui/gfx/gl/gl_surface_egl.cc

@@ -66,8 +66,6 @@ bool GLSurfaceEGL::InitializeOneOff() {
     EGL_BLUE_SIZE, 8,
     EGL_GREEN_SIZE, 8,
     EGL_RED_SIZE, 8,
-    EGL_DEPTH_SIZE, 16,
-    EGL_STENCIL_SIZE, 8,
     EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
     EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT,
     EGL_NONE

ui/gfx/gl/gl_surface_glx.cc

@@ -214,8 +214,6 @@ bool PbufferGLSurfaceGLX::Initialize() {
     GLX_BLUE_SIZE, 8,
     GLX_GREEN_SIZE, 8,
     GLX_RED_SIZE, 8,
-    GLX_DEPTH_SIZE, 16,  // TODO(apatrick): support optional depth buffer
-    GLX_STENCIL_SIZE, 8,
     GLX_RENDER_TYPE, GLX_RGBA_BIT,
     GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT,
     GLX_DOUBLEBUFFER, False,

ui/gfx/gl/gl_surface_wgl.cc

@@ -27,8 +27,8 @@ const PIXELFORMATDESCRIPTOR kPixelFormatDescriptor = {
   8, 0,                    // 8 bit alpha
   0,                       // No accumulation buffer.
   0, 0, 0, 0,              // Ignore accumulation bits.
-  24,                      // 24 bit z-buffer size.
-  8,                       // 8-bit stencil buffer.
+  0,                       // no z-buffer.
+  0,                       // no stencil buffer.
   0,                       // No aux buffer.
   PFD_MAIN_PLANE,          // Main drawing plane (not overlay).
   0,                       // Reserved.