Some changes to service protocol before we land 1.13.

runtime/vm/service/service.md

 # Dart VM Service Protocol 3.0
 
 > Please post feedback to the [observatory-discuss group][discuss-list]
 
 This document describes of _version 3.0_ of the Dart VM Service Protocol. This
 protocol is used to communicate with a running Dart Virtual Machine.
 
 To use the Service Protocol, start the VM with the *--observe* flag.
 The VM will start a webserver which services protocol requests via WebSocket.
 It is possible to make HTTP (non-WebSocket) requests,
 but this does not allow access to VM _events_ and is not documented
 here.
 
 The Service Protocol uses [JSON-RPC 2.0][].
 
 [JSON-RPC 2.0]: http://www.jsonrpc.org/specification
 
 **Table of Contents**
 
 - [RPCs, Requests, and Responses](#rpcs-requests-and-responses)
 - [Events](#events)
 - [Types](#types)
 - [IDs and Names](#ids-and-names)
 - [Versioning](#versioning)
 - [Private RPCs, Types, and Properties](#private-rpcs-types-and-properties)
 - [Public RPCs](#public-rpcs)
         - [addBreakpoint](#addbreakpoint)
+        - [addBreakpointWithScriptUri](#addbreakpointwithscripturi)
         - [addBreakpointAtEntry](#addbreakpointatentry)
         - [evaluate](#evaluate)
         - [evaluateInFrame](#evaluateinframe)
         - [getFlagList](#getflaglist)
         - [getIsolate](#getisolate)
         - [getObject](#getobject)
         - [getStack](#getstack)
         - [getVersion](#getversion)
         - [getVM](#getvm)
         - [pause](#pause)
@@ skipping 327 matching lines @@
 ReturnType methodName(parameterType parameterName [optional)
 ```
 
 A description of the return types and parameter types is provided
 in the section on [public types](#public-types).
 
 ### addBreakpoint
 
 ```
 Breakpoint addBreakpoint(string isolateId,
-                         string scriptId [optional],
-                         string scriptUri [optional],
+                         string scriptId,
                          int line,
                          int column [optional])
 ```
 
 The _addBreakpoint_ RPC is used to add a breakpoint at a specific line
 of some script.
 
-The _scriptId_ or _scriptUri_ parameter is used to specify the target
-script. One of these two parameters must always be provided.
+The _scriptId_ parameter is used to specify the target script.
 
 The _line_ parameter is used to specify the target line for the
 breakpoint. If there are multiple possible breakpoints on the target
+line, then the VM will place the breakpoint at the location which
+would execute soonest. If it is not possible to set a breakpoint at
+the target line, the breakpoint will be added at the next possible
+breakpoint location within the same function.
+
+The _column_ parameter may be optionally specified.  This is useful
+for targeting a specific breakpoint on a line with multiple possible
+breakpoints.
+
+If no breakpoint is possible at that line, the _102_ (Cannot add
+breakpoint) error code is returned.
+
+Note that breakpoints are added and removed on a per-isolate basis.
+
+See [Breakpoint](#breakpoint).
+
+### addBreakpointWithScriptUri
+
+```
+Breakpoint addBreakpointWithScriptUri(string isolateId,
+                                      string scriptUri,
+                                      int line,
+                                      int column [optional])
+```
+
+The _addBreakpoint_ RPC is used to add a breakpoint at a specific line
+of some script.  This RPC is useful when a script has not yet been
+assigned an id, for example, if a script is in a deferred library
+which has not yet been loaded.
+
+The _scriptUri_ parameter is used to specify the target script.
+
+The _line_ parameter is used to specify the target line for the
+breakpoint. If there are multiple possible breakpoints on the target
 line, then the VM will place the breakpoint at the location which
 would execute soonest. If it is not possible to set a breakpoint at
 the target line, the breakpoint will be added at the next possible
 breakpoint location within the same function.
 
 The _column_ parameter may be optionally specified.  This is useful
 for targeting a specific breakpoint on a line with multiple possible
 breakpoints.
 
 If no breakpoint is possible at that line, the _102_ (Cannot add
@@ skipping 1249 matching lines @@
   // The number of live ports for this isolate.
   int livePorts;
 
   // Will this isolate pause when exiting?
   bool pauseOnExit;
 
   // The last pause event delivered to the isolate. If the isolate is
   // running, this will be a resume event.
   Event pauseEvent;
 
-  // The entry function for this isolate.
-  //
-  // Guaranteed to be initialized when the IsolateRunnable event fires.
-  @Function entry [optional];
-
   // The root library for this isolate.
   //
   // Guaranteed to be initialized when the IsolateRunnable event fires.
   @Library rootLib [optional];
 
   // A list of all libraries for this isolate.
   //
   // Guaranteed to be initialized when the IsolateRunnable event fires.
   @Library[] libraries;
 
@@ skipping 437 matching lines @@
 
   // A list of isolates running in the VM.
   @Isolate[] isolates;
 }
 ```
 
 ## Revision History
 
 version | comments
 ------- | --------
-1.0 draft 1 | initial revision
-1.1 | Describe protocol version 2.0.
-1.2 | Describe protocol version 3.0.  Added UnresolvedSourceLocation.  Added Sentinel return to getIsolate.
+1.0 | initial revision
+2.0 | Describe protocol version 2.0.
+3.0 | Describe protocol version 3.0.  Added UnresolvedSourceLocation.  Added Sentinel return to getIsolate.  Add AddedBreakpointWithScriptUri.  Removed Isolate.entry.
 
 
 [discuss-list]: https://groups.google.com/a/dartlang.org/forum/#!forum/observatory-discuss