WebGL GL_RGB emulation to support IOSurfaces on Mac.

third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
index 1cb6bc8050b82f73b8e28287c394a1dbe04d9bf8..72192be78037e0ae37ce5113eccd62a753787dca 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
@@ -1512,6 +1512,7 @@ void WebGL2RenderingContextBase::drawArraysInstanced(GLenum mode, GLint first, G
     if (!validateDrawArrays("drawArraysInstanced"))
         return;
 
+    ScopedRGBEmulationColorMask emulationColorMask(contextGL(), m_colorMask, m_drawingBuffer.get());
     clearIfComposited();
     contextGL()->DrawArraysInstancedANGLE(mode, first, count, instanceCount);
     markContextChanged(CanvasChanged);
@@ -1527,6 +1528,7 @@ void WebGL2RenderingContextBase::drawElementsInstanced(GLenum mode, GLsizei coun
         return;
     }
 
+    ScopedRGBEmulationColorMask emulationColorMask(contextGL(), m_colorMask, m_drawingBuffer.get());
     clearIfComposited();
     contextGL()->DrawElementsInstancedANGLE(mode, count, type, reinterpret_cast<void*>(static_cast<intptr_t>(offset)), instanceCount);
     markContextChanged(CanvasChanged);
@@ -1542,6 +1544,7 @@ void WebGL2RenderingContextBase::drawRangeElements(GLenum mode, GLuint start, GL
         return;
     }
 
+    ScopedRGBEmulationColorMask emulationColorMask(contextGL(), m_colorMask, m_drawingBuffer.get());
     clearIfComposited();
     contextGL()->DrawRangeElements(mode, start, end, count, type, reinterpret_cast<void*>(static_cast<intptr_t>(offset)));
     markContextChanged(CanvasChanged);
@@ -1552,6 +1555,7 @@ void WebGL2RenderingContextBase::drawBuffers(const Vector<GLenum>& buffers)
     if (isContextLost())
         return;
 
+    ScopedRGBEmulationColorMask emulationColorMask(contextGL(), m_colorMask, m_drawingBuffer.get());
     GLsizei n = buffers.size();
     const GLenum* bufs = buffers.data();
     for (GLsizei i = 0; i < n; ++i) {