Initial checkin of gRPC to third_party/

third_party/grpc/src/core/census/README.md

-/*
- * Copyright (C) 2013 Google Inc. All rights reserved.
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+-->
 
-#ifndef AnimatableShapeValue_h
-#define AnimatableShapeValue_h
+# Census - a resource measurement and tracing system
 
-#include "core/CoreExport.h"
-#include "core/animation/animatable/AnimatableValue.h"
-#include "core/style/ShapeValue.h"
+This directory contains code for Census, which will ultimately provide the
+following features for any gRPC-using system:
+* A [dapper](http://research.google.com/pubs/pub36356.html)-like tracing
+  system, enabling tracing across a distributed infrastructure.
+* RPC statistics and measurements for key metrics, such as latency, bytes
+  transferred, number of errors etc.
+* Resource measurement framework which can be used for measuring custom
+  metrics. Through the use of [tags](#Tags), these can be broken down across
+  the entire distributed stack.
+* Easy integration of the above with
+  [Google Cloud Trace](https://cloud.google.com/tools/cloud-trace) and
+  [Google Cloud Monitoring](https://cloud.google.com/monitoring/).
 
-namespace blink {
+## Concepts
 
-class CORE_EXPORT AnimatableShapeValue final : public AnimatableValue {
-public:
-    ~AnimatableShapeValue() override { }
-    static PassRefPtr<AnimatableShapeValue> create(ShapeValue* shape)
-    {
-        return adoptRef(new AnimatableShapeValue(shape));
-    }
-    ShapeValue* getShapeValue() const { return m_shape.get(); }
+### Context
 
-protected:
-    PassRefPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const override;
-    bool usesDefaultInterpolationWith(const AnimatableValue*) const override;
+### Operations
 
-private:
-    AnimatableShapeValue(ShapeValue* shape)
-        : m_shape(shape)
-    {
-        ASSERT(m_shape);
-    }
-    AnimatableType type() const override { return TypeShapeValue; }
-    bool equalTo(const AnimatableValue*) const override;
+### Tags
 
-    Persistent<ShapeValue> m_shape;
-};
+### Metrics
 
-DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableShapeValue, isShapeValue());
+## API
 
-} // namespace blink
+### Internal/RPC API
 
-#endif // AnimatableShapeValue_h
+### External/Client API
+
+### RPC API
+
+## Files in this directory
+
+Note that files and functions in this directory can be split into two
+categories:
+* Files that define core census library functions. Functions etc. in these
+  files are named census\_\*, and constitute the core census library
+  functionality. At some time in the future, these will become a standalone
+  library.
+* Files that define functions etc. that provide a convenient interface between
+  grpc and the core census functionality. These files are all named
+  grpc\_\*.{c,h}, and define function names beginning with grpc\_census\_\*.
+