Implement EXT_draw_buffers WebGL extention support in command buffer.

A few things:
1) I only hooked up with desktop GL backend, i.e., GL_ARB_draw_buffers. Will add GLES support later.
2) Probably we need to do something to enable this for Pepper3D also? If yes, will do so in a seperate CL.
3) I didn't add the wordarounds for Mac/Linux driver bugs. Will do so in a seperate CL.

BUG=180397
TEST=gpu_unittests, webgl conformance tests
Review URL: https://codereview.chromium.org/12545014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@188129 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 120 insertions, 0 deletions

diff --git a/gpu/GLES2/gl2chromium_autogen.h b/gpu/GLES2/gl2chromium_autogen.h
index c53d1ce..fa099e6 100644
--- a/gpu/GLES2/gl2chromium_autogen.h
+++ b/gpu/GLES2/gl2chromium_autogen.h
@@ -225,6 +225,7 @@
 #define glLoseContextCHROMIUM GLES2_GET_FUN(LoseContextCHROMIUM)
 #define glInsertSyncPointCHROMIUM GLES2_GET_FUN(InsertSyncPointCHROMIUM)
 #define glWaitSyncPointCHROMIUM GLES2_GET_FUN(WaitSyncPointCHROMIUM)
+#define glDrawBuffersEXT GLES2_GET_FUN(DrawBuffersEXT)
 
 #endif  // GPU_GLES2_GL2CHROMIUM_AUTOGEN_H_
 
diff --git a/gpu/GLES2/gl2extchromium.h b/gpu/GLES2/gl2extchromium.h
index 6609fd4..b8dbc30 100644
--- a/gpu/GLES2/gl2extchromium.h
+++ b/gpu/GLES2/gl2extchromium.h
@@ -413,6 +413,125 @@ typedef void (GL_APIENTRYP PFNGLBLITFRAMEBUFFEREXTPROC) (
     GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter);
 #endif  /* GL_EXT_framebuffer_blit */
 
+/* GL_EXT_draw_buffers */
+#ifndef GL_EXT_draw_buffers
+#define GL_EXT_draw_buffers 1
+
+#ifdef GL_GLEXT_PROTOTYPES
+GL_APICALL void GL_APIENTRY glDrawBuffersEXT(
+    GLsizei n, const GLenum* bufs);
+#endif
+typedef void (GL_APIENTRYP PFNGLDRAWBUFFERSEXTPROC) (
+    GLsizei n, const GLenum* bufs);
+
+#ifndef GL_COLOR_ATTACHMENT0_EXT
+#define GL_COLOR_ATTACHMENT0_EXT 0x8CE0
+#endif
+#ifndef GL_COLOR_ATTACHMENT1_EXT
+#define GL_COLOR_ATTACHMENT1_EXT 0x8CE1
+#endif
+#ifndef GL_COLOR_ATTACHMENT2_EXT
+#define GL_COLOR_ATTACHMENT2_EXT 0x8CE2
+#endif
+#ifndef GL_COLOR_ATTACHMENT3_EXT
+#define GL_COLOR_ATTACHMENT3_EXT 0x8CE3
+#endif
+#ifndef GL_COLOR_ATTACHMENT4_EXT
+#define GL_COLOR_ATTACHMENT4_EXT 0x8CE4
+#endif
+#ifndef GL_COLOR_ATTACHMENT5_EXT
+#define GL_COLOR_ATTACHMENT5_EXT 0x8CE5
+#endif
+#ifndef GL_COLOR_ATTACHMENT6_EXT
+#define GL_COLOR_ATTACHMENT6_EXT 0x8CE6
+#endif
+#ifndef GL_COLOR_ATTACHMENT7_EXT
+#define GL_COLOR_ATTACHMENT7_EXT 0x8CE7
+#endif
+#ifndef GL_COLOR_ATTACHMENT8_EXT
+#define GL_COLOR_ATTACHMENT8_EXT 0x8CE8
+#endif
+#ifndef GL_COLOR_ATTACHMENT9_EXT
+#define GL_COLOR_ATTACHMENT9_EXT 0x8CE9
+#endif
+#ifndef GL_COLOR_ATTACHMENT10_EXT
+#define GL_COLOR_ATTACHMENT10_EXT 0x8CEA
+#endif
+#ifndef GL_COLOR_ATTACHMENT11_EXT
+#define GL_COLOR_ATTACHMENT11_EXT 0x8CEB
+#endif
+#ifndef GL_COLOR_ATTACHMENT12_EXT
+#define GL_COLOR_ATTACHMENT12_EXT 0x8CEC
+#endif
+#ifndef GL_COLOR_ATTACHMENT13_EXT
+#define GL_COLOR_ATTACHMENT13_EXT 0x8CED
+#endif
+#ifndef GL_COLOR_ATTACHMENT14_EXT
+#define GL_COLOR_ATTACHMENT14_EXT 0x8CEE
+#endif
+#ifndef GL_COLOR_ATTACHMENT15_EXT
+#define GL_COLOR_ATTACHMENT15_EXT 0x8CEF
+#endif
+
+#ifndef GL_DRAW_BUFFER0_EXT
+#define GL_DRAW_BUFFER0_EXT 0x8825
+#endif
+#ifndef GL_DRAW_BUFFER1_EXT
+#define GL_DRAW_BUFFER1_EXT 0x8826
+#endif
+#ifndef GL_DRAW_BUFFER2_EXT
+#define GL_DRAW_BUFFER2_EXT 0x8827
+#endif
+#ifndef GL_DRAW_BUFFER3_EXT
+#define GL_DRAW_BUFFER3_EXT 0x8828
+#endif
+#ifndef GL_DRAW_BUFFER4_EXT
+#define GL_DRAW_BUFFER4_EXT 0x8829
+#endif
+#ifndef GL_DRAW_BUFFER5_EXT
+#define GL_DRAW_BUFFER5_EXT 0x882A
+#endif
+#ifndef GL_DRAW_BUFFER6_EXT
+#define GL_DRAW_BUFFER6_EXT 0x882B
+#endif
+#ifndef GL_DRAW_BUFFER7_EXT
+#define GL_DRAW_BUFFER7_EXT 0x882C
+#endif
+#ifndef GL_DRAW_BUFFER8_EXT
+#define GL_DRAW_BUFFER8_EXT 0x882D
+#endif
+#ifndef GL_DRAW_BUFFER9_EXT
+#define GL_DRAW_BUFFER9_EXT 0x882E
+#endif
+#ifndef GL_DRAW_BUFFER10_EXT
+#define GL_DRAW_BUFFER10_EXT 0x882F
+#endif
+#ifndef GL_DRAW_BUFFER11_EXT
+#define GL_DRAW_BUFFER11_EXT 0x8830
+#endif
+#ifndef GL_DRAW_BUFFER12_EXT
+#define GL_DRAW_BUFFER12_EXT 0x8831
+#endif
+#ifndef GL_DRAW_BUFFER13_EXT
+#define GL_DRAW_BUFFER13_EXT 0x8832
+#endif
+#ifndef GL_DRAW_BUFFER14_EXT
+#define GL_DRAW_BUFFER14_EXT 0x8833
+#endif
+#ifndef GL_DRAW_BUFFER15_EXT
+#define GL_DRAW_BUFFER15_EXT 0x8834
+#endif
+
+#ifndef GL_MAX_COLOR_ATTACHMENTS_EXT
+#define GL_MAX_COLOR_ATTACHMENTS_EXT 0x8CDF
+#endif
+
+#ifndef GL_MAX_DRAW_BUFFERS_EXT
+#define GL_MAX_DRAW_BUFFERS_EXT 0x8824
+#endif
+
+#endif  /* GL_EXT_draw_buffers */
+
 /* GL_CHROMIUM_resize */
 #ifndef GL_CHROMIUM_resize
 #define GL_CHROMIUM_resize 1