Add TraceBuffer log to all Functions (plus small tweaks to function-view)

runtime/vm/trace_buffer.h

Index: runtime/vm/trace_buffer.h
diff --git a/runtime/vm/trace_buffer.h b/runtime/vm/trace_buffer.h
index f8b1c78de406e15451c8fb8cefbb36dcf68dd095..e6b325e310a9075d942678e6eda6ad91976428be 100644
--- a/runtime/vm/trace_buffer.h
+++ b/runtime/vm/trace_buffer.h
@@ -11,6 +11,7 @@
 
 namespace dart {
 
+class JSONObject;
 class JSONStream;
 
 struct TraceBufferEntry {
@@ -23,9 +24,13 @@ struct TraceBufferEntry {
 
 class TraceBuffer {
  public:
-  static const intptr_t kDefaultCapacity = 1024;
+  static const intptr_t kInitialCapacity = 16;
+  static const intptr_t kMaximumCapacity = 1024;
 
-  explicit TraceBuffer(intptr_t capacity = kDefaultCapacity);
+  // TraceBuffer starts with kInitialCapacity and will expand itself until
+  // it reaches kMaximumCapacity.
+  TraceBuffer(intptr_t initial_capacity = kInitialCapacity,
+              intptr_t maximum_capacity = kMaximumCapacity);
   ~TraceBuffer();
 
   void Clear();
@@ -36,20 +41,26 @@ class TraceBuffer {
   void Trace(const char* message);
   void TraceF(const char* format, ...) PRINTF_ATTRIBUTE(2, 3);
 
+  void PrintToJSONObject(JSONObject* obj) const;
   void PrintToJSONStream(JSONStream* stream) const;
 
+  intptr_t capacity() const { return capacity_; }
+
  private:
   void Init();
+  void Resize(intptr_t capacity);
   void Cleanup();
   void Fill(TraceBufferEntry* entry, int64_t micros, char* msg);
   void AppendTrace(int64_t micros, char* message);
 
   TraceBufferEntry* ring_;
-  const intptr_t ring_capacity_;
+  intptr_t size_;
+  intptr_t capacity_;
   intptr_t ring_cursor_;
+  const intptr_t max_capacity_;
 
   intptr_t RingIndex(intptr_t i) const {
-    return i % ring_capacity_;
+    return i % capacity_;
   }
 
   DISALLOW_COPY_AND_ASSIGN(TraceBuffer);