Plumb through EGL_NV_post_sub_buffer and GLX_MESA_copy_sub_buffer.

These two extensions allow a partial swap: just pushing part of the backbuffer to the front buffer. This will allow the WK compositor to push a partial update to the screen instead of a full frame update (https://bugs.webkit.org/show_bug.cgi?id=70533).

We should be able to do something similar for TOUCHUI ImageTransportSurfaces (hence the hooks into GLSurface and the glPostSubBufferCHROMIUM command).

Review URL: http://codereview.chromium.org/8512005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109625 0039d316-1c4b-4281-b951-d872f2087c98

25 files changed, 232 insertions, 3 deletions

diff --git a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
index ab7379c..39dfc04 100644
--- a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
+++ b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
@@ -292,6 +292,20 @@ void WebGraphicsContext3DCommandBufferImpl::prepareTexture() {
 #endif
 }
 
+void WebGraphicsContext3DCommandBufferImpl::postSubBufferCHROMIUM(
+    int x, int y, int width, int height) {
+  // Same flow control as WebGraphicsContext3DCommandBufferImpl::prepareTexture
+  // (see above).
+  RenderViewImpl* renderview =
+      web_view_ ? RenderViewImpl::FromWebView(web_view_) : NULL;
+  if (renderview)
+    renderview->OnViewContextSwapBuffersPosted();
+  gl_->PostSubBufferCHROMIUM(x, y, width, height);
+  context_->Echo(base::Bind(
+      &WebGraphicsContext3DCommandBufferImpl::OnSwapBuffersComplete,
+      weak_ptr_factory_.GetWeakPtr()));
+}
+
 void WebGraphicsContext3DCommandBufferImpl::reshape(int width, int height) {
   cached_width_ = width;
   cached_height_ = height;
diff --git a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
index d5871ce..6b052aa 100644
--- a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
+++ b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
@@ -79,6 +79,7 @@ class WebGraphicsContext3DCommandBufferImpl
 
   virtual WebGLId getPlatformTextureId();
   virtual void prepareTexture();
+  virtual void postSubBufferCHROMIUM(int x, int y, int width, int height);
 
   virtual void activeTexture(WGC3Denum texture);
   virtual void attachShader(WebGLId program, WebGLId shader);
diff --git a/gpu/GLES2/gl2ext.h b/gpu/GLES2/gl2ext.h
index 71a3df0..28b3119 100644
--- a/gpu/GLES2/gl2ext.h
+++ b/gpu/GLES2/gl2ext.h
@@ -1349,6 +1349,19 @@ typedef void (GL_APIENTRYP PFNGLENABLEFEATURECHROMIUM) (const GLchar *feature);
 #endif
 #endif
 
+/* GL_CHROMIUM_post_sub_buffer */
+#ifndef GL_CHROMIUM_post_sub_buffer
+#define GL_CHROMIUM_post_sub_buffer 1
+#ifdef GL_GLEXT_PROTOTYPES
+#define glPostSubBufferCHROMIUM GLES2_GET_FUN(PostSubBufferCHROMIUM)
+#if !defined(GLES2_USE_CPP_BINDINGS)
+GL_APICALL void GL_APIENTRY glPostSubBufferCHROMIUM (GLint x, GLint y, GLint width, GLint height);
+#endif
+#else
+typedef void (GL_APIENTRYP PFNGLPOSTSUBBUFFERCHROMIUM) (GLint x, GLint y, GLint width, GLint height);
+#endif
+#endif
+
 /* GL_ARB_robustness */
 /* This extension is subsetted for the moment, incorporating only the
  * enums necessary to describe the reasons that we might encounter for
diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index e1051b4..36dad3f 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -224,6 +224,7 @@ GL_APICALL GLuint       GL_APIENTRY glCreateStreamTextureCHROMIUM (GLuint textur
 GL_APICALL void         GL_APIENTRY glDestroyStreamTextureCHROMIUM (GLuint texture);
 GL_APICALL void         GL_APIENTRY glPlaceholder453CHROMIUM (void);
 GL_APICALL void         GL_APIENTRY glGetTranslatedShaderSourceANGLE (GLidShader shader, GLsizeiNotNegative bufsize, GLsizei* length, char* source);
+GL_APICALL void         GL_APIENTRY glPostSubBufferCHROMIUM (GLint x, GLint y, GLint width, GLint height);
 """
 
 # This is the list of all commmands that will be generated and their Id.
@@ -433,6 +434,7 @@ _CMD_ID_TABLE = {
   'GetMultipleIntegervCHROMIUM':                               454,
   'GetProgramInfoCHROMIUM':                                    455,
   'GetTranslatedShaderSourceANGLE':                            456,
+  'PostSubBufferCHROMIUM':                                     457,
 }
 
 # This is a list of enum names and their valid values. It is used to map
@@ -1517,6 +1519,13 @@ _FUNCTION_INFO = {
     'chromium': True,
   },
   'PixelStorei': {'type': 'Manual'},
+  'PostSubBufferCHROMIUM': {
+      'type': 'Custom',
+      'impl_func': False,
+      'unit_test': False,
+      'extension': True,
+      'chromium': True,
+  },
   'RenderbufferStorage': {
     'decoder_func': 'DoRenderbufferStorage',
     'gl_test_func': 'glRenderbufferStorageEXT',
diff --git a/gpu/command_buffer/client/gles2_c_lib_autogen.h b/gpu/command_buffer/client/gles2_c_lib_autogen.h
index e046662..40c7102 100644
--- a/gpu/command_buffer/client/gles2_c_lib_autogen.h
+++ b/gpu/command_buffer/client/gles2_c_lib_autogen.h
@@ -586,6 +586,9 @@ void GLES2GetTranslatedShaderSourceANGLE(
   gles2::GetGLContext()->GetTranslatedShaderSourceANGLE(
       shader, bufsize, length, source);
 }
+void GLES2PostSubBufferCHROMIUM(GLint x, GLint y, GLint width, GLint height) {
+  gles2::GetGLContext()->PostSubBufferCHROMIUM(x, y, width, height);
+}
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_C_LIB_AUTOGEN_H_
 
diff --git a/gpu/command_buffer/client/gles2_cmd_helper_autogen.h b/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
index 0705fb3..2a5d6d7 100644
--- a/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
+++ b/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
@@ -1247,5 +1247,11 @@
     c.Init(shader, bucket_id);
   }
 
+  void PostSubBufferCHROMIUM(GLint x, GLint y, GLint width, GLint height) {
+    gles2::PostSubBufferCHROMIUM& c =
+        GetCmdSpace<gles2::PostSubBufferCHROMIUM>();
+    c.Init(x, y, width, height);
+  }
+
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_CMD_HELPER_AUTOGEN_H_
 
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index 5fce838..6d402c5 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -2649,5 +2649,21 @@ void GLES2Implementation::DestroyStreamTextureCHROMIUM(GLuint texture) {
   helper_->DestroyStreamTextureCHROMIUM(texture);
 }
 
+void GLES2Implementation::PostSubBufferCHROMIUM(
+    GLint x, GLint y, GLint width, GLint height) {
+  GPU_CLIENT_LOG("[" << this << "] PostSubBufferCHROMIUM("
+      << x << ", " << y << ", " << width << ", " << height << ")");
+  TRACE_EVENT0("gpu", "GLES2::PostSubBufferCHROMIUM");
+
+  // Same flow control as GLES2Implementation::SwapBuffers (see comments there).
+  swap_buffers_tokens_.push(helper_->InsertToken());
+  helper_->PostSubBufferCHROMIUM(x, y, width, height);
+  helper_->CommandBufferHelper::Flush();
+  if (swap_buffers_tokens_.size() > kMaxSwapBuffers + 1) {
+    helper_->WaitForToken(swap_buffers_tokens_.front());
+    swap_buffers_tokens_.pop();
+  }
+}
+
 }  // namespace gles2
 }  // namespace gpu
diff --git a/gpu/command_buffer/client/gles2_implementation_autogen.h b/gpu/command_buffer/client/gles2_implementation_autogen.h
index d8f6a5c..0721c79 100644
--- a/gpu/command_buffer/client/gles2_implementation_autogen.h
+++ b/gpu/command_buffer/client/gles2_implementation_autogen.h
@@ -1303,5 +1303,7 @@ void GetTranslatedShaderSourceANGLE(
     *length = max_size;
   }
 }
+void PostSubBufferCHROMIUM(GLint x, GLint y, GLint width, GLint height);
+
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_IMPLEMENTATION_AUTOGEN_H_
 
diff --git a/gpu/command_buffer/common/gles2_cmd_format_autogen.h b/gpu/command_buffer/common/gles2_cmd_format_autogen.h
index ef34bad..cb54dda 100644
--- a/gpu/command_buffer/common/gles2_cmd_format_autogen.h
+++ b/gpu/command_buffer/common/gles2_cmd_format_autogen.h
@@ -9165,6 +9165,52 @@ COMPILE_ASSERT(offsetof(GetTranslatedShaderSourceANGLE, shader) == 4,
 COMPILE_ASSERT(offsetof(GetTranslatedShaderSourceANGLE, bucket_id) == 8,
                OffsetOf_GetTranslatedShaderSourceANGLE_bucket_id_not_8);
 
+struct PostSubBufferCHROMIUM {
+  typedef PostSubBufferCHROMIUM ValueType;
+  static const CommandId kCmdId = kPostSubBufferCHROMIUM;
+  static const cmd::ArgFlags kArgFlags = cmd::kFixed;
+
+  static uint32 ComputeSize() {
+    return static_cast<uint32>(sizeof(ValueType));  // NOLINT
+  }
+
+  void SetHeader() {
+    header.SetCmd<ValueType>();
+  }
+
+  void Init(GLint _x, GLint _y, GLint _width, GLint _height) {
+    SetHeader();
+    x = _x;
+    y = _y;
+    width = _width;
+    height = _height;
+  }
+
+  void* Set(void* cmd, GLint _x, GLint _y, GLint _width, GLint _height) {
+    static_cast<ValueType*>(cmd)->Init(_x, _y, _width, _height);
+    return NextCmdAddress<ValueType>(cmd);
+  }
+
+  gpu::CommandHeader header;
+  int32 x;
+  int32 y;
+  int32 width;
+  int32 height;
+};
+
+COMPILE_ASSERT(sizeof(PostSubBufferCHROMIUM) == 20,
+               Sizeof_PostSubBufferCHROMIUM_is_not_20);
+COMPILE_ASSERT(offsetof(PostSubBufferCHROMIUM, header) == 0,
+               OffsetOf_PostSubBufferCHROMIUM_header_not_0);
+COMPILE_ASSERT(offsetof(PostSubBufferCHROMIUM, x) == 4,
+               OffsetOf_PostSubBufferCHROMIUM_x_not_4);
+COMPILE_ASSERT(offsetof(PostSubBufferCHROMIUM, y) == 8,
+               OffsetOf_PostSubBufferCHROMIUM_y_not_8);
+COMPILE_ASSERT(offsetof(PostSubBufferCHROMIUM, width) == 12,
+               OffsetOf_PostSubBufferCHROMIUM_width_not_12);
+COMPILE_ASSERT(offsetof(PostSubBufferCHROMIUM, height) == 16,
+               OffsetOf_PostSubBufferCHROMIUM_height_not_16);
+
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_FORMAT_AUTOGEN_H_
 
diff --git a/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h b/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
index a150a58..9c414a9 100644
--- a/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
+++ b/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
@@ -3559,5 +3559,24 @@ TEST_F(GLES2FormatTest, GetTranslatedShaderSourceANGLE) {
       next_cmd, sizeof(cmd));
 }
 
+TEST_F(GLES2FormatTest, PostSubBufferCHROMIUM) {
+  PostSubBufferCHROMIUM& cmd = *GetBufferAs<PostSubBufferCHROMIUM>();
+  void* next_cmd = cmd.Set(
+      &cmd,
+      static_cast<GLint>(11),
+      static_cast<GLint>(12),
+      static_cast<GLint>(13),
+      static_cast<GLint>(14));
+  EXPECT_EQ(static_cast<uint32>(PostSubBufferCHROMIUM::kCmdId),
+            cmd.header.command);
+  EXPECT_EQ(sizeof(cmd), cmd.header.size * 4u);
+  EXPECT_EQ(static_cast<GLint>(11), cmd.x);
+  EXPECT_EQ(static_cast<GLint>(12), cmd.y);
+  EXPECT_EQ(static_cast<GLint>(13), cmd.width);
+  EXPECT_EQ(static_cast<GLint>(14), cmd.height);
+  CheckBytesWrittenMatchesExpectedSize(
+      next_cmd, sizeof(cmd));
+}
+
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_FORMAT_TEST_AUTOGEN_H_
 
diff --git a/gpu/command_buffer/common/gles2_cmd_ids_autogen.h b/gpu/command_buffer/common/gles2_cmd_ids_autogen.h
index 0c9aa01..498c625 100644
--- a/gpu/command_buffer/common/gles2_cmd_ids_autogen.h
+++ b/gpu/command_buffer/common/gles2_cmd_ids_autogen.h
@@ -211,6 +211,7 @@
   OP(GetMultipleIntegervCHROMIUM)                              /* 454 */ \
   OP(GetProgramInfoCHROMIUM)                                   /* 455 */ \
   OP(GetTranslatedShaderSourceANGLE)                           /* 456 */ \
+  OP(PostSubBufferCHROMIUM)                                    /* 457 */ \
 
 enum CommandId {
   kStartPoint = cmd::kLastCommonId,  // All GLES2 commands start after this.
diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index 5d6fe74..64c7222 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -7,6 +7,7 @@
 #include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "ui/gfx/gl/gl_implementation.h"
+#include "ui/gfx/gl/gl_surface.h"
 
 namespace gpu {
 namespace gles2 {
@@ -357,6 +358,12 @@ void FeatureInfo::AddFeatures(const char* desired_features) {
   feature_flags_.enable_texture_half_float_linear =
       enable_texture_half_float_linear;
   feature_flags_.npot_ok = npot_ok;
+
+  if (ext.Desire("GL_CHROMIUM_post_sub_buffer") &&
+      gfx::GLSurface::GetCurrent() &&
+      gfx::GLSurface::GetCurrent()->SupportsPostSubBuffer()) {
+    AddExtensionString("GL_CHROMIUM_post_sub_buffer");
+  }
 }
 
 void FeatureInfo::AddExtensionString(const std::string& str) {
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index f31effa..fc12352 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -5740,6 +5740,20 @@ error::Error GLES2DecoderImpl::HandlePixelStorei(
   return error::kNoError;
 }
 
+error::Error GLES2DecoderImpl::HandlePostSubBufferCHROMIUM(
+    uint32 immediate_data_size, const gles2::PostSubBufferCHROMIUM& c) {
+  TRACE_EVENT0("gpu", "GLES2DecoderImpl::HandlePostSubBufferCHROMIUM");
+  if (!surface_->SupportsPostSubBuffer()) {
+    SetGLError(GL_INVALID_OPERATION,
+               "glPostSubBufferCHROMIUM: command not supported by surface");
+    return error::kNoError;
+  }
+  if (surface_->PostSubBuffer(c.x, c.y, c.width, c.height))
+    return error::kNoError;
+  else
+    return error::kLostContext;
+}
+
 error::Error GLES2DecoderImpl::GetAttribLocationHelper(
     GLuint client_id, uint32 location_shm_id, uint32 location_shm_offset,
     const std::string& name_str) {
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_unittest_3_autogen.h b/gpu/command_buffer/service/gles2_cmd_decoder_unittest_3_autogen.h
index e5b9d40..c60e869 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_unittest_3_autogen.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_unittest_3_autogen.h
@@ -15,5 +15,6 @@
 // TODO(gman): DestroyStreamTextureCHROMIUM
 
 // TODO(gman): GetTranslatedShaderSourceANGLE
+// TODO(gman): PostSubBufferCHROMIUM
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_UNITTEST_3_AUTOGEN_H_
 
diff --git a/ui/gfx/gl/generate_bindings.py b/ui/gfx/gl/generate_bindings.py
index 2e1a1e0..4207533 100644
--- a/ui/gfx/gl/generate_bindings.py
+++ b/ui/gfx/gl/generate_bindings.py
@@ -363,6 +363,9 @@ EGL_FUNCTIONS = [
     'EGLDisplay dpy, EGLSurface surface, EGLNativePixmapType target'],
 ['__eglMustCastToProperFunctionPointerType', ['eglGetProcAddress'],
     'const char* procname'],
+['EGLBoolean', ['eglPostSubBufferNV'],
+    'EGLDisplay dpy, EGLSurface surface, '
+    'EGLint x, EGLint y, EGLint width, EGLint height'],
 ['EGLBoolean', ['eglQuerySurfacePointerANGLE'],
     'EGLDisplay dpy, EGLSurface surface, EGLint attribute, void** value'],
 ]
@@ -396,6 +399,9 @@ WGL_FUNCTIONS = [
 GLX_FUNCTIONS = [
 ['XVisualInfo*', ['glXChooseVisual'],
     'Display* dpy, int screen, int* attribList'],
+['void', ['glXCopySubBufferMESA'],
+    'Display* dpy, GLXDrawable drawable, '
+    'int x, int y, int width, int height'],
 ['GLXContext', ['glXCreateContext'],
     'Display* dpy, XVisualInfo* vis, GLXContext shareList, int direct'],
 ['void', ['glXBindTexImageEXT'],
diff --git a/ui/gfx/gl/gl_surface.cc b/ui/gfx/gl/gl_surface.cc
index 34d4464..78cada4 100644
--- a/ui/gfx/gl/gl_surface.cc
+++ b/ui/gfx/gl/gl_surface.cc
@@ -94,6 +94,14 @@ unsigned int GLSurface::GetBackingFrameBufferObject() {
   return 0;
 }
 
+bool GLSurface::SupportsPostSubBuffer() {
+  return false;
+}
+
+bool GLSurface::PostSubBuffer(int x, int y, int width, int height) {
+  return false;
+}
+
 bool GLSurface::OnMakeCurrent(GLContext* context) {
   return true;
 }
diff --git a/ui/gfx/gl/gl_surface.h b/ui/gfx/gl/gl_surface.h
index 5843a9c..150182e 100644
--- a/ui/gfx/gl/gl_surface.h
+++ b/ui/gfx/gl/gl_surface.h
@@ -50,6 +50,10 @@ class GL_EXPORT GLSurface : public base::RefCounted<GLSurface> {
   // FBO. Otherwise returns 0.
   virtual unsigned int GetBackingFrameBufferObject();
 
+  // Copy part of the backbuffer to the frontbuffer.
+  virtual bool SupportsPostSubBuffer();
+  virtual bool PostSubBuffer(int x, int y, int width, int height);
+
   static bool InitializeOneOff();
 
   // Called after a context is made current with this surface. Returns false
diff --git a/ui/gfx/gl/gl_surface_egl.cc b/ui/gfx/gl/gl_surface_egl.cc
index 6f6d630..8301bc4 100644
--- a/ui/gfx/gl/gl_surface_egl.cc
+++ b/ui/gfx/gl/gl_surface_egl.cc
@@ -173,7 +173,8 @@ EGLNativeDisplayType GLSurfaceEGL::GetNativeDisplay() {
 NativeViewGLSurfaceEGL::NativeViewGLSurfaceEGL(bool software,
                                                gfx::PluginWindowHandle window)
     : window_(window),
-      surface_(NULL)
+      surface_(NULL),
+      supports_post_sub_buffer_(false)
 {
   software_ = software;
 }
@@ -190,11 +191,18 @@ bool NativeViewGLSurfaceEGL::Initialize() {
     return false;
   }
 
+  static const EGLint egl_window_attributes_sub_buffer[] = {
+    EGL_POST_SUB_BUFFER_SUPPORTED_NV, EGL_TRUE,
+    EGL_NONE
+  };
+
   // Create a surface for the native window.
   surface_ = eglCreateWindowSurface(GetDisplay(),
                                     GetConfig(),
                                     window_,
-                                    NULL);
+                                    gfx::g_EGL_NV_post_sub_buffer ?
+                                        egl_window_attributes_sub_buffer :
+                                        NULL);
 
   if (!surface_) {
     LOG(ERROR) << "eglCreateWindowSurface failed with error "
@@ -203,6 +211,13 @@ bool NativeViewGLSurfaceEGL::Initialize() {
     return false;
   }
 
+  EGLint surfaceVal;
+  EGLBoolean retVal = eglQuerySurface(GetDisplay(),
+                                      surface_,
+                                      EGL_POST_SUB_BUFFER_SUPPORTED_NV,
+                                      &surfaceVal);
+  supports_post_sub_buffer_ = (surfaceVal && retVal) == EGL_TRUE;
+
   return true;
 }
 
@@ -247,6 +262,21 @@ EGLSurface NativeViewGLSurfaceEGL::GetHandle() {
   return surface_;
 }
 
+bool NativeViewGLSurfaceEGL::SupportsPostSubBuffer() {
+  return supports_post_sub_buffer_;
+}
+
+bool NativeViewGLSurfaceEGL::PostSubBuffer(
+    int x, int y, int width, int height) {
+  DCHECK(supports_post_sub_buffer_);
+  if (!eglPostSubBufferNV(GetDisplay(), surface_, x, y, width, height)) {
+    VLOG(1) << "eglPostSubBufferNV failed with error "
+            << GetLastEGLErrorString();
+    return false;
+  }
+  return true;
+}
+
 PbufferGLSurfaceEGL::PbufferGLSurfaceEGL(bool software, const gfx::Size& size)
     : size_(size),
       surface_(NULL) {
diff --git a/ui/gfx/gl/gl_surface_egl.h b/ui/gfx/gl/gl_surface_egl.h
index de68fc8..352c052 100644
--- a/ui/gfx/gl/gl_surface_egl.h
+++ b/ui/gfx/gl/gl_surface_egl.h
@@ -43,7 +43,7 @@ class GL_EXPORT GLSurfaceEGL : public GLSurface {
   static EGLDisplay GetSoftwareDisplay();
   static EGLNativeDisplayType GetNativeDisplay();
 
-protected:
+ protected:
   bool software_;
 
  private:
@@ -63,10 +63,13 @@ class NativeViewGLSurfaceEGL : public GLSurfaceEGL {
   virtual bool SwapBuffers();
   virtual gfx::Size GetSize();
   virtual EGLSurface GetHandle();
+  virtual bool SupportsPostSubBuffer();
+  virtual bool PostSubBuffer(int x, int y, int width, int height);
 
  private:
   gfx::PluginWindowHandle window_;
   EGLSurface surface_;
+  bool supports_post_sub_buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeViewGLSurfaceEGL);
 };
diff --git a/ui/gfx/gl/gl_surface_glx.cc b/ui/gfx/gl/gl_surface_glx.cc
index 2f2380f..373bc85 100644
--- a/ui/gfx/gl/gl_surface_glx.cc
+++ b/ui/gfx/gl/gl_surface_glx.cc
@@ -203,6 +203,17 @@ void* NativeViewGLSurfaceGLX::GetConfig() {
   return config_;
 }
 
+bool NativeViewGLSurfaceGLX::SupportsPostSubBuffer() {
+  return g_GLX_MESA_copy_sub_buffer;
+}
+
+bool NativeViewGLSurfaceGLX::PostSubBuffer(
+    int x, int y, int width, int height) {
+  DCHECK(SupportsPostSubBuffer());
+  glXCopySubBufferMESA(g_display, window_, x, y, width, height);
+  return true;
+}
+
 PbufferGLSurfaceGLX::PbufferGLSurfaceGLX(const gfx::Size& size)
   : size_(size),
     config_(NULL),
diff --git a/ui/gfx/gl/gl_surface_glx.h b/ui/gfx/gl/gl_surface_glx.h
index 7784a79..f880b66 100644
--- a/ui/gfx/gl/gl_surface_glx.h
+++ b/ui/gfx/gl/gl_surface_glx.h
@@ -53,6 +53,8 @@ class GL_EXPORT NativeViewGLSurfaceGLX : public GLSurfaceGLX {
   virtual gfx::Size GetSize();
   virtual void* GetHandle();
   virtual void* GetConfig();
+  virtual bool SupportsPostSubBuffer();
+  virtual bool PostSubBuffer(int x, int y, int width, int height);
 
  protected:
   NativeViewGLSurfaceGLX();
diff --git a/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc b/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc
index 71a8a70..4f8044b 100644
--- a/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc
+++ b/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc
@@ -758,6 +758,11 @@ void WebGraphicsContext3DInProcessCommandBufferImpl::prepareTexture() {
   context_->SwapBuffers();
 }
 
+void WebGraphicsContext3DInProcessCommandBufferImpl::postSubBufferCHROMIUM(
+    int x, int y, int width, int height) {
+  gl_->PostSubBufferCHROMIUM(x, y, width, height);
+}
+
 void WebGraphicsContext3DInProcessCommandBufferImpl::reshape(
     int width, int height) {
   cached_width_ = width;
diff --git a/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h b/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h
index 9a65ae9..1ba8624 100644
--- a/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h
+++ b/webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h
@@ -77,6 +77,7 @@ class WebGraphicsContext3DInProcessCommandBufferImpl
 
   virtual WebGLId getPlatformTextureId();
   virtual void prepareTexture();
+  virtual void postSubBufferCHROMIUM(int x, int y, int width, int height);
 
   virtual void activeTexture(WGC3Denum texture);
   virtual void attachShader(WebGLId program, WebGLId shader);
diff --git a/webkit/gpu/webgraphicscontext3d_in_process_impl.cc b/webkit/gpu/webgraphicscontext3d_in_process_impl.cc
index 835bd61..a1c8fef 100644
--- a/webkit/gpu/webgraphicscontext3d_in_process_impl.cc
+++ b/webkit/gpu/webgraphicscontext3d_in_process_impl.cc
@@ -333,6 +333,12 @@ void WebGraphicsContext3DInProcessImpl::prepareTexture() {
   }
 }
 
+void WebGraphicsContext3DInProcessImpl::postSubBufferCHROMIUM(
+    int x, int y, int width, int height) {
+  DCHECK(gl_surface_->SupportsPostSubBuffer());
+  gl_surface_->PostSubBuffer(x, y, width, height);
+}
+
 namespace {
 
 int CreateTextureObject(GLenum target) {
diff --git a/webkit/gpu/webgraphicscontext3d_in_process_impl.h b/webkit/gpu/webgraphicscontext3d_in_process_impl.h
index ac23af4..49ae61f 100644
--- a/webkit/gpu/webgraphicscontext3d_in_process_impl.h
+++ b/webkit/gpu/webgraphicscontext3d_in_process_impl.h
@@ -82,6 +82,7 @@ class WebGraphicsContext3DInProcessImpl : public WebGraphicsContext3D {
 
   virtual WebGLId getPlatformTextureId();
   virtual void prepareTexture();
+  virtual void postSubBufferCHROMIUM(int x, int y, int width, int height);
 
   virtual void synthesizeGLError(WGC3Denum error);
   virtual void* mapBufferSubDataCHROMIUM(WGC3Denum target, WGC3Dintptr offset,