command_buffer: Implement CHROMIUM_framebuffer_mixed_samples extension

gpu/command_buffer/build_gles2_cmd_buffer.py

Index: gpu/command_buffer/build_gles2_cmd_buffer.py
diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index 76708f5e1cfa1fb302df3a2d16c6ced5a9f41595..7301ab03baa3ff7a6d88b522e0850a67ae46c6cd 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -150,6 +150,18 @@ _STATES = {
       {'name': 'stencil_clear', 'type': 'GLint', 'default': '0'},
     ],
   },
+  'CoverageModulationCHROMIUM': {
+    'type': 'Normal',
+    'func': 'CoverageModulationNV',
+    'extension_flag': 'chromium_framebuffer_mixed_samples',
+    'states': [
+      { 'enum': 'GL_COVERAGE_MODULATION_CHROMIUM',
+        'name': 'coverage_modulation',
+        'type': 'GLenum',
+        'default': 'GL_NONE',
+      },
+    ]
+  },
   'BlendColor': {
     'type': 'Normal',
     'func': 'BlendColor',
@@ -650,6 +662,12 @@ _NAMED_TYPE_INFO = {
       'GL_LINEAR_MIPMAP_LINEAR',
     ],
   },
+  'CoverageModulationComponents': {
+    'type': 'GLenum',
+    'valid': [
+      'GL_RGB', 'GL_RGBA', 'GL_ALPHA', 'GL_NONE'
+    ],
+  },
   'FrameBufferTarget': {
     'type': 'GLenum',
     'valid': [
@@ -2385,6 +2403,14 @@ _FUNCTION_INFO = {
   'CopyBufferSubData': {
     'unsafe': True,
   },
+  'CoverageModulationCHROMIUM': {
+    'type': 'StateSet',
+    'state': 'CoverageModulationCHROMIUM',
+    'decoder_func': 'glCoverageModulationNV',
+    'chromium': True,
+    'extension': 'CHROMIUM_framebuffer_mixed_samples',
+    'extension_flag': 'chromium_framebuffer_mixed_samples',
+  },
   'CreateAndConsumeTextureCHROMIUM': {
     'decoder_func': 'DoCreateAndConsumeTextureCHROMIUM',
     'impl_func': False,