Add command buffer support for GL_RGB CHROMIUM image emulation.

third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h

Index: third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h
diff --git a/third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h b/third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h
index 3018b84f49c18f78bade1ed9777e8f150fe15586..c2e18ad7ec4e3feadb46361fc3d1aaee24f42832 100644
--- a/third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h
+++ b/third_party/WebKit/public/platform/WebGraphicsContext3DProvider.h
@@ -36,6 +36,8 @@
 class GrContext;
 
 namespace gpu {
+struct Capabilities;
+
 namespace gles2 {
 class GLES2Interface;
 }
@@ -51,6 +53,7 @@ public:
     virtual WebGraphicsContext3D* context3d() = 0;
     virtual gpu::gles2::GLES2Interface* contextGL() = 0;
     virtual GrContext* grContext() = 0;
+    virtual gpu::Capabilities getCapabilities() = 0;
 
     virtual void setLostContextCallback(WebClosure) = 0;
     virtual void setErrorMessageCallback(WebFunction<void(const char* msg, int32_t id)>) = 0;