Add 'dart:debugger' library

runtime/vm/debugger.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 2257 matching lines @@
   stack_trace_ = stack_trace;
   SignalPausedEvent(top_frame, bpt->src_bpt_);
   HandleSteppingRequest(stack_trace_);
   stack_trace_ = NULL;
   if (bpt->IsInternal()) {
     RemoveInternalBreakpoints();
   }
 }
 
 
+void Debugger::ExplicitBreakpoint() {

[hausner, 2015/05/05 00:16:27]

SignalDebugBreak()  ?

[Cutch, 2015/05/05 02:38:53]

I went with BreakHere and changed the behaviour. PTAL.

+  // We ignore this breakpoint when the VM is executing code invoked
+  // by the debugger to evaluate variables values, or when we see a nested
+  // breakpoint or exception event.
+  if (ignore_breakpoints_ || IsPaused() || !HasEventHandler()) {
+    return;
+  }
+
+  DebuggerStackTrace* stack_trace = CollectStackTrace();
+  ASSERT(stack_trace->Length() > 0);
+  ActivationFrame* top_frame = stack_trace->FrameAt(0);
+  ASSERT(top_frame != NULL);
+
+  ASSERT(stack_trace_ == NULL);
+  stack_trace_ = stack_trace;
+  SignalPausedEvent(top_frame, NULL);
+  HandleSteppingRequest(stack_trace_);
+  stack_trace_ = NULL;
+}
+
+
 void Debugger::Initialize(Isolate* isolate) {
   if (initialized_) {
     return;
   }
   isolate_ = isolate;
 
   // Use the isolate's control port as the isolate_id for debugging.
   // This port will be used as a unique ID to represent the isolate in the
   // debugger wire protocol messages.
   isolate_id_ = isolate->main_port();
@@ skipping 379 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart