ogle/program: return the PCs of the breakpoints set. LGTM=r R=r https://golang.org/cl/135610043

diff --git a/program/client/client.go b/program/client/client.go
index 9a770c3..66187d6 100644
--- a/program/client/client.go
+++ b/program/client/client.go

@@ -194,12 +194,13 @@
 	panic("unimplemented")
 }
 
-func (p *Program) Breakpoint(address string) error {
+func (p *Program) Breakpoint(address string) ([]uint64, error) {
 	req := proxyrpc.BreakpointRequest{
 		Address: address,
 	}
 	var resp proxyrpc.BreakpointResponse
-	return p.client.Call("Server.Breakpoint", &req, &resp)
+	err := p.client.Call("Server.Breakpoint", &req, &resp)
+	return resp.PCs, err
 }
 
 func (p *Program) DeleteBreakpoint(address string) error {

diff --git a/program/program.go b/program/program.go
index 5e51152..ac7325a 100644
--- a/program/program.go
+++ b/program/program.go

@@ -60,7 +60,7 @@
 	// The address is the same mini-language accepted by Eval,
 	// which permits setting multiple breakpoints using a regular
 	// expression to match a set of symbols.
-	Breakpoint(address string) error
+	Breakpoint(address string) (PCs []uint64, err error)
 
 	// DeleteBreakpoint removes the breakpoint at the specified
 	// address. TODO: Probably the wrong interface.

diff --git a/program/proxyrpc/proxyrpc.go b/program/proxyrpc/proxyrpc.go
index e201f1f..3784268 100644
--- a/program/proxyrpc/proxyrpc.go
+++ b/program/proxyrpc/proxyrpc.go

@@ -70,6 +70,7 @@
 }
 
 type BreakpointResponse struct {
+	PCs []uint64
 }
 
 type EvalRequest struct {

diff --git a/program/server/server.go b/program/server/server.go
index 72c8a5a..3536379 100644
--- a/program/server/server.go
+++ b/program/server/server.go

@@ -429,6 +429,7 @@
 		}
 		bp.pc = pc
 		s.breakpoints[pc] = bp
+		resp.PCs = append(resp.PCs, pc)
 	}
 
 	return nil