rpc: Strip down the base RPC client interface. (#6971)

* rpc: Strip down the base RPC client interface.

Prior to this change, the RPC client interface requires implementing the entire
Service interface, but most of the methods of Service are not needed by the
concrete clients. Dissociate the Client interface from the Service interface.

- Extract only those methods of Service that are necessary to make the existing
  clients work.

- Update the clients to combine Start/Onstart and Stop/OnStop. This does not
  change what the clients do to start or stop. Only the websocket clients make
  use of this functionality anyway.

  The websocket implementation uses some plumbing from the BaseService helper.
  We should be able to excising that entirely, but the current interface
  dependencies among the clients would require a much larger change, and one
  that leaks into other (non-RPC) packages.

  As a less-invasive intermediate step, preserve the existing client behaviour
  (and tests) by extracting the necessary subset of the BaseService
  functionality to an analogous RunState helper for clients. I plan to obsolete
  that type in a future PR, but for now this makes a useful waypoint.

Related:
- Clean up client implementations.
- Update mocks.

rpc/client/mocks/client.go

@@ -10,8 +10,6 @@ import (
 
 	coretypes "github.com/tendermint/tendermint/rpc/coretypes"
 
-	log "github.com/tendermint/tendermint/libs/log"
-
 	mock "github.com/stretchr/testify/mock"
 
 	types "github.com/tendermint/tendermint/types"
@@ -542,74 +540,6 @@ func (_m *Client) NumUnconfirmedTxs(_a0 context.Context) (*coretypes.ResultUncon
 	return r0, r1
 }
 
-// OnReset provides a mock function with given fields:
-func (_m *Client) OnReset() error {
-	ret := _m.Called()
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func() error); ok {
-		r0 = rf()
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
-
-// OnStart provides a mock function with given fields:
-func (_m *Client) OnStart() error {
-	ret := _m.Called()
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func() error); ok {
-		r0 = rf()
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
-
-// OnStop provides a mock function with given fields:
-func (_m *Client) OnStop() {
-	_m.Called()
-}
-
-// Quit provides a mock function with given fields:
-func (_m *Client) Quit() <-chan struct{} {
-	ret := _m.Called()
-
-	var r0 <-chan struct{}
-	if rf, ok := ret.Get(0).(func() <-chan struct{}); ok {
-		r0 = rf()
-	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(<-chan struct{})
-		}
-	}
-
-	return r0
-}
-
-// Reset provides a mock function with given fields:
-func (_m *Client) Reset() error {
-	ret := _m.Called()
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func() error); ok {
-		r0 = rf()
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
-
-// SetLogger provides a mock function with given fields: _a0
-func (_m *Client) SetLogger(_a0 log.Logger) {
-	_m.Called(_a0)
-}
-
 // Start provides a mock function with given fields:
 func (_m *Client) Start() error {
 	ret := _m.Called()
@@ -661,20 +591,6 @@ func (_m *Client) Stop() error {
 	return r0
 }
 
-// String provides a mock function with given fields:
-func (_m *Client) String() string {
-	ret := _m.Called()
-
-	var r0 string
-	if rf, ok := ret.Get(0).(func() string); ok {
-		r0 = rf()
-	} else {
-		r0 = ret.Get(0).(string)
-	}
-
-	return r0
-}
-
 // Subscribe provides a mock function with given fields: ctx, subscriber, query, outCapacity
 func (_m *Client) Subscribe(ctx context.Context, subscriber string, query string, outCapacity ...int) (<-chan coretypes.ResultEvent, error) {
 	_va := make([]interface{}, len(outCapacity))
@@ -824,8 +740,3 @@ func (_m *Client) Validators(ctx context.Context, height *int64, page *int, perP
 
 	return r0, r1
 }
-
-// Wait provides a mock function with given fields:
-func (_m *Client) Wait() {
-	_m.Called()
-}